List of auxiliary Interstate Highways
|Dwight D. Eisenhower National System of Interstate and Defense Highways|
Highway shield for Interstate 295
Interstate Highways in the 48 contiguous states
|Formed:||June 29, 1956|
|Interstates:||Interstate X (I-X)|
The auxiliary Interstate Highways (also called three-digit Interstate Highways) are a supplemental subset of the freeways within the Interstate Highway System of the United States. Similar to the mainline Interstate Highways, these highways also meet all Interstate Highway Standards (with rare exceptions), they receive the same percentage of federal funding (90%), and they comply with other federal standards.
Auxiliary routes are generally classified as spur routes (which connect to the parent route at one end), bypasses (which connect to the parent route at both ends), or beltways, which form a complete circle intersecting the parent route at two locations. There are some routes which connect to the parent route at one end, but connect to another route at the other end; some states treat these as spurs while others treat these as bypasses.
These shorter auxiliary routes branch off of main routes and are numbered based on the number of the parent route, such that all I-x95 routes are supplemental routes for I-95. While some exceptions do exist, generally spur routes are numbered with an odd hundreds digit (such as I-395), while bypasses and beltways are numbered with an even hundreds digit (such as I-695). Because longer interstates may have many such supplemental routes, the numbers may repeat from state to state along their route, but they will not repeat within a state.
Terminology and guidelines
The first digit of the three digits usually determines whether a route is a bypass, spur, or beltway. The last two digits are derived from the main Interstate Highway. For instance, I-515 contains an odd number in the first digit (5), and this indicates that this freeway is a spur. The last two digits signify the highway's origin. In this case, the "15" in I-515 shows that it is a supplement to I-15.
Numerous exceptions to the standard numbering guidelines exist in many places. This can be for a number of reasons. In some cases, original routes were changed, extended, or abandoned, leaving discrepancies in the system. In other cases, it may not be possible to use the proper number because the limited set of available numbers has been exhausted, causing a "non-standard" number to be used.
- It may serve another section of a city or metropolitan area not served by the main freeway (most often the central business district), terminating at a regular city street/avenue or at a substandard freeway, such as I-180 in Lincoln, Nebraska.
- It may represent the first portion of a contemplated extended freeway, one that downgrades to below Interstate standards with plans to upgrade it later on. An example is I-540 in Arkansas.
- It may connect two unrelated Interstate highways—such as I-390 in New York State and I-355 in Illinois do.
- Note that states differ on their interpretation of the numbering convention in this case. In the I-390 example above, the route has both ends at Interstates, but not at the same Interstate on both ends, and is assigned an odd first digit. Another example is I-275 in Tennessee: it is a connector between I-40 and I-75 (a similar case of having both ends at Interstates but not at the same Interstate) and is assigned an even first digit.
- I-110 in California links I-10 with the Port of Los Angeles. This freeway was built before Interstate Highways as the Harbor Freeway. Later, it was adopted into the Interstate Highway System.
- I-180 in North-Central Pennsylvania connects Williamsport and Lycoming County with I-80 in Milton, which does not actually enter Lycoming County. I-180 also serves as a connection to those traveling to New York and I-86 via U.S. Route 15 and the Future I-99 Corridor at its western terminus.
- I-190 in New York connects the cities of Niagara Falls and Buffalo with I-90.
Sometimes, a three-digit Interstate Highway branches off from another three-digit Interstate Highway. These spurs do not connect directly with their parent highways, but are associated with them via the three-digit highways they do intersect with.
- I-380 in Northern California is located at the San Francisco Bay Area. This highway begins at I-280, and it connects with US 101 and San Francisco International Airport.
- I-190 in Massachusetts branches off from I-290 near Worcester.
- I-795 in Baltimore County, Maryland branches off from I-695.
A bypass route may traverse around a city, or may run through it with the mainline bypassing. In a typical 3-digit Interstate Highway, bypasses usually have both its two termini junctioned with another Interstate highway. Bypass routes are preceded by an even number in the first digit.
- I-215 in Utah travels part of the perimeter of Salt Lake City.
- I-220 in Louisiana serves as a bypass of downtown Shreveport.
- I-440 forms a loop around the south side of Nashville.
In the case of an auxiliary Interstate highway which has both ends at Interstates but not the same Interstate, some states treat these as bypasses while others treat these as spurs — see Spur route above.
A beltway (also known as a loop route) completely surrounds a metropolitan city, and it is often connected with multiple junctions to other routes. Unlike other auxiliary Interstate Highways, beltways do not have termini, however they have a place where the highway mileage resets to zero. Beltways are also preceded by an even number in the first digit.
Some examples of beltways include:
- I-275 in Ohio, Kentucky and Indiana encircles the city of Cincinnati.
- I-465 in Indiana encircles the city of Indianapolis.
- I-495 in Maryland and Virginia encircles the city of Washington, D.C. and is referred to as "The Capital Beltway".
- Note: the table sorts the route numbers by parent highway.
|Number||Length (mi)||Length (km)||Southern or western terminus||Northern or eastern terminus||Formed||Removed||Notes|
|H-201||4.10||6.60||H-1 in Halawa||H-1 in Honolulu||1989||current||Signed as Route 78 until 2004|
|I-105||17.32||27.87||SR 1 in El Segundo||I-605 in Norwalk||1963||current||Replaced segments of SR 42|
|I-205||12.97||20.87||I-580 near Tracy||I-5 near Tracy||1970||current|
|I-305||6.00||9.66||I-80 in West Sacramento||I-80 Bus/US 50/SR 99 in Sacramento||1981||current||Unsigned|
|I-405||72.15||116.11||I-5 in Irvine||I-5 in Mission Hills||1964||current|
|I-505||32.98||53.08||I-80 in Vacaville||I-5 in Dunnigan||1977||current||Originally part of Interstate I-5W|
|I-605||27.40||44.10||I-405 in Seal Beach||I-210 in Irwindale||1964||current|
|I-805||28.02||45.09||I-5 in San Ysidro||I-5 in Sorrento Valley||1959||current|
|I-905||8.96||14.42||I-5 in San Ysidro||Fed. 2 at the United States-Mexico border in Otay Mesa||proposed||—||Currently SR 905, proposed to be signed as an Interstate|
|I-105||3.49||5.62||OR 99 in Eugene||I-5 in Springfield||2011||current|
|I-405||3.53||5.68||I-5 in Portland||I-5 in Portland||—||—|
|I‑205||36.64||58.97||I-5 in Tualatin, OR||I-5 in Salmon Creek, WA||1975||current|
|I‑405||30.30||48.76||I-5/SR 518 in Tukwila||I-5/SR 525 in Lynnwood||1964||current|
|I‑605||—||—||—||—||proposed||—||Proposed to bypass Seattle|
|I‑705||1.50||2.41||I-5/SR 7 in Tacoma||—||1990||current||Schuster Parkway in Tacoma|
|I-210||—||—||I-10 in Mobile (original southern terminus)||I-65 in Prichard||—||—||Currently I-165, the route number was decommissioned because it had no connection to I-10|
|I-410||—||—||I-10/I-17 in Phoenix||I-10 in Phoenix||—||—||Now part of I-10 in Phoenix, Arizona|
|I-510||—||—||I-10/SR 51 in Phoenix||SR 101 in Phoenix||—||—||Currently designated as Arizona State Route 51 (Piestewa Freeway)|
|I-710||—||—||I-10 in Tucson||N Campbell Avenue/E 6th Street in Tucson||—||—||Mostly never built freeway that was to connect to University of Arizona campus from I-10|
|I-110||20.43||32.88||SR 47 in San Pedro, Los Angeles||I-10/SR 110 in Los Angeles||1978||current||Originally part of US 66, then signed as SR 11|
|I-210||48.72||78.41||I-5 in Sylmar||SR 57/SR 210 in Glendora||1964||current||Segment from SR 57 east to I-10 is still signed as the state highway SR 210, formerly SR 30 prior to 2007.|
|I-710||19.66||31.64||Terminal Island in Long Beach||Valley Boulevard in Alhambra||1983||current||Originally signed as SR 7|
|I-110||6.94||11.17||US 98 Bus near Pensacola||I-10 near Pensacola||1969||current|
|I-110||8.89||14.31||I-10 in Baton Rouge||US 61 in Baton Rouge||1964||current|
|I-210||12.40||19.96||I-10 west of Lake Charles||I-10 east of Lake Charles||1964||current|
|I-310||11.25||18.11||US 90/LA 3127 in Boutte||I-10 west of Kenner||1983||current|
|I-310||2.70||4.35||US 90 Bus. in New Orleans||I-10 in New Orleans||1964||1969||Cancelled Vieux Carré Riverfront Expressway|
|I-410||1.90||3.06||LA 67 in Baton Rouge||I-10 in Baton Rouge||1961||1964||Renumbered as I-110|
|I-410||—||—||I-10 west of New Orleans||I-10 in Eastern New Orleans||1969||1977||Cancelled southern bypass of New Orleans|
|I-510||3.04||4.89||LA 47 in New Orleans||I-10/LA 47 in New Orleans||1992||current|
|I-610||4.52||7.27||I-10 at Metairie–New Orleans line||I-10 in New Orleans||1965||current|
|I-910||9.70||15.61||US 90 Bus in Marrero||I-10/US 90 Bus. in New Orleans||1999||current||Signed as part of US 90 Bus. and Future I-49|
|I-110||4.10||6.60||US 90 in Biloxi||I-10 in D'Iberville||1988||current|
|I-310||—||—||US 90 near the Port of Gulfport||I-10 in Gulfport||proposed||—||Future spur into Gulfport, MS|
|I-110||0.92||1.48||Av Abraham Lincoln at the United States-Mexico border in El Paso||I-10 in El Paso||1967||current||Shortest signed Interstate in the country|
|I-410||49.49||79.65||Beltway around San Antonio||1959||current|
|I-610||37.97||61.11||Beltway around Houston||1975||current|
|I-215||54.50||87.71||I-15 in Murrieta||I-15 in Devore||1982||current||Originally signed as I-15E, then SR 215|
|I-115||1.19||1.92||I-15/I-90 in Butte||Iron Street in Butte||1971||current|
|I-315||0.83||1.34||I-15 in Great Falls||I-15 Bus/US 89 in Great Falls||1960||current||Unsigned|
|I‑215||11.10||17.86||I-15/Clark County Route 215 near Paradise||I-515/US 93/SR 564 in Henderson||1996||current|
|I‑515||20.54||33.06||US 93/US 95 in Henderson||I-15/US 93/US 95 in Las Vegas||1976||current||Not signed until 1994|
|I-215||29.02||46.70||I-80 in Salt Lake City||I-15 in North Salt Lake||1963||current|
|I‑516||6.49||10.44||SR 21/SR 204 in Savannah||SR 21 in Garden City||1985||current|
|I‑420||5.40||8.69||I-285 in College Park||I-20 in Atlanta||1983||1986||Never built, was planned to bypass Atlanta|
|I‑520||16.14||25.97||I-20 in Augusta, GA||I-20 in North Augusta, SC||1980||current|
|I-220||17.62||28.36||I-20/LA 3132 in Shreveport||I-20 in Bossier City||1979||current|
|I-420||10.20||16.42||I-20 in West Monroe||I-20 in Monroe||1957||1964||Cancelled bypass of Monroe|
|I-220||12.01||19.33||I-20 in Jackson||I-55 in Ridgeland||1981||current|
|I-820||35.17||56.60||I-20 in Fort Worth||I-20 / US 287 in Fort Worth||1959||current|
|I-222||—||—||I-22 near Birmingham, AL||Interstate 422 near Birmingham, AL||proposed||—|
|I-422||—||—||I-20/I-59/I-459/US 11 in Bessemer||I-59 in Argo||proposed||—|
|I-124||1.97||3.17||I-24 in Chattanooga||US 27 in Chattanooga||1960||current||Unsigned|
|I-225||12.00||19.31||I-25 in Denver||I-70 in Aurora||1976||current|
|I-126||3.68||5.92||I-26 in Columbia||US 21/US 76/US 176/US 321 in Columbia||1961||current|
|I-326||5.24||8.43||I-26 in Cayce||SC 48 in Columbia||1976||1995||Now part of I-77, formerly unsigned|
|I-526||19.26||31.00||US 17 in Charleston||I-526 Bus/US 17 in Mount Pleasant||1989||current|
|I-129||3.48||5.60||US 20/US 75/US 77 in South Sioux City, NE||I-29/US 20/US 75 in Sioux City, IA||1976||current|
|I-229||14.97||24.09||I-29 in St. Joseph||I-29/US 59/US 71 in St. Joseph||1986||current|
|I-229||11.33||18.23||I-29 in Sioux Falls||I-90 near Sioux Falls||1966||current|
|I-130||5||8||I-30/I-49 in Texarkana||US 59/US 71 near Texarkana||2000||2014||Now part of I-49|
|I-430||12.93||20.81||I-30/US 67 in Little Rock||I-40/US 65 in Little Rock||1980||current|
|I-530||46.65||75.08||US 65 in Pine Bluff||I-30/I-440 in Little Rock||1999||current|
|I-630||7.40||11.91||I-430 near Little Rock||I-30 in Little Rock||1985||current|
|I-235||13.78||22.18||I-35/I-80 in West Des Moines||I-35/I-80 near Des Moines||1961||current|
|I-135||95.74||154.08||Kan. Tpk./I-35 in Wichita||I-70/US 81 in Salina||1976||current|
|I-235||16.52||26.59||I-135/US 81 in Wichita||I-135/US 81/K-15/K-254 in Wichita||1965||current|
|I-335||50.13||80.68||I-35/Kan. Tpk./US 50 in Emporia||I-470/Kan. Tpk. in Topeka||1987||current|
|I-435||80.81||130.05||Beltway around Kansas City, KS and Kansas City, MO||1965||current|
|I-635||8.90||14.32||I-35 in Overland Park, KS||I-29/US 71 in Kansas City, MO||1968||current|
|I-335||2.74||4.41||I-94 in Minneapolis||I-35W in Minneapolis||1964||1978||Cancelled|
|I-535||2.78||4.47||I-35/US 53 in Duluth, MN||US 53/WIS 35 in Superior, WI||1971||current|
|I-235||5.36||8.63||I-35/I-40 in Oklahoma City||I-44 in Oklahoma City||1989||current|
|I-635||37.00||59.55||SH 121 in Grapevine||I-20 in Balch Springs||1959||current|
|I-238||2.23||3.59||I-880 in San Leandro, CA||I-580/SR 238 in Castro Valley, CA||1983||current||Considered an auxiliary route of I-80 in California; there is no I-38|
|I-440||9.96||16.03||I-30/I-530 near Little Rock||I-40/AR 440 near Little Rock||2003||current|
|I-540||15.87||25.54||US 271/AR 253 near Fort Smith||I-40 in Van Buren||1965||current|
|I‑140||6.79||10.93||US 17/US 421 near Navassa||I-40/US 17 in Wilmington||2008||current|
|I‑240||9.54||15.35||I-26/I-40/US 74 near Asheville||I-40/US 74A in Asheville||1980||current|
|I‑440||16.77||26.99||I-40/US 1/US 64 near Cary||I-40 near Raleigh||1991||current|
|I‑540||25.84||41.59||I-40 near Durham||I-87/US 64/US 264 near Knightdale||1997||current|
|I‑840||5.77||9.29||I-40/I-73/US 421 in Greensboro||I-40/I-85/I-785/I-85 Bus. in Greensboro||2011||current|
|I-240||16.22||26.10||I-44/US 62 in Oklahoma City||I-40/US 270 in Oklahoma City||1965||current|
|I-440||9.96||16.03||I-40/I-240 near Oklahoma City||I-35 in Oklahoma City||—||—||Now part of I-44|
|I-140||11.17||17.98||I-40 near Farragut||US 129 near Alcoa||1987||current|
|I-240||19.27||31.01||I-40 in Memphis||I-40 in Memphis||1970||current|
|I-440||7.64||12.30||I-40 in Nashville||I-24 in Nashville||1987||current|
|I-640||7.03||11.31||I-40 in Knoxville||I-40 in Knoxville||1982||current|
|I-840||77.28||124.37||I-40 near Dickson||I-40 near Lebanon||2016||current|
|I-244||15.75||25.35||I-44 in Tulsa||I-44 in Tulsa||1970||current|
|I-444||2.51||4.04||I-244 in Tulsa||I-244 in Tulsa||1970||current||Unsigned|
|I-345||1.40||2.25||I-30/I-45 in Dallas, TX||US 75 in Dallas, TX||1973||current||Unsigned|
|I-555||49.8||80.1||I-55 in Turrell||AR 91 in Jonesboro||2016||current|
|I-155||32.13||51.71||I-74 in Morton||I-55 in Lincoln||1992||current|
|I-255||30.82||49.60||I-55/I-270 in Mehlville, MO||I-270/IL 255 in Pontoon Beach, IL||1986||current|
|I-355||32.51||52.32||I-80 in New Lenox||I-290 in Itasca||1989||current|
|I-155||15.93||25.64||I-55 near Hayti, MO||US 51 at Dyersburg, TN||1980||current|
|I-255||—||—||I-55/I-240 in Memphis||I-40 in Memphis||—||—||Now part of I-55 and I-240|
|I-359||2.30||3.70||I-20/I-59 in southern Tuscaloosa||15th Street in downtown Tuscaloosa||1983||current|
|I-459||32.80||52.79||I-20/I-59 in Bessemer||I-59 in Trussville||1984||current|
|I-759||4.50||7.24||I-59 in Attalla||US-411/SR-759 in Gadsden||1986||current|
|I-164||21.39||34.42||US 41/Veterans Memorial Parkway in Evansville, IN||I-69 in Evansville, IN||1990||2014||Decommissioned; now part of I-69|
|I-264||22.93||36.90||I-64 in Louisville||I-71 in Louisville||1956||current|
|I-264||25.07||40.35||I-64/I-664 in Chesapeake||Parks Ave in Virginia Beach||1960||current|
|I-464||4.71||7.58||I-64 in Chesapeake||I-264 in Norfolk||1960||current|
|I-564||3.03||4.88||SR 337||I-64 in Norfolk||1970||current|
|I-664||20.21||32.52||I-64/I-264 in Norfolk||I-64 in Hampton||1971||current|
|I-165||4.90||7.89||US-43 in Mobile||I-65 in Mobile||1994||current|
|I-565||21.40||34.44||I-65/US-72/SR-20 in Decatur||US-72 in Huntsville||1991||current|
|I-165||2.7||4.3||I-65/I-70 in Indianapolis||38th Street in Indianapolis||1978||1981||Was to be a spur linking from I-65/70 to 38th Street entirely with Indianapolis|
|I-265||6.73||10.83||I-64 in New Albany, IN||SR 62/SR 265 in Clarksville, IN||1977||current||Connected with I-265 in Kentucky on December 18, 2016, with the completion of the East End Bridge|
|I-465||52.79||84.96||Beltway around Indianapolis||1970||current|
|I-865||4.72||7.60||I-65 near Indianapolis||I-465 near Indianapolis||2002||current|
|I-265||24.48||39.40||I-65/KY 841 in Heritage Creek||I-71/KY 841 in Prospect||1977||current||To be connected with I-265 in Indiana in late 2016 with the completion of the East End Bridge|
|I-565||—||—||Owensboro, KY||I-65 in Bowling Green, KY||proposed||—||Proposed to be designated along William H. Natcher Parkway once put into interstate standards|
|I-265||—||—||I-40 in Nashville||I-65 in Nashville||—||—||Now part of I-65|
|I-469||30.83||49.62||I-69 in Fort Wayne||I-69 in Fort Wayne||1995||current|
|I-169||49||79||I-24 near Hopkinsville, Kentucky||I-69 in Nortonville, Kentucky||2017||current||New designation along the former Pennyrile Parkway|
|I-369||—||—||Future I-69/Pennyrile Parkway in Henderson||US 60 in Owensboro||proposed||—|
|I-269||4.20||6.76||I-55/I-69 in Hernando, MS||I-69 in Millington, TN||2015||current||Currently under construction; partially open|
|I-169||—||—||Union City, TN||Martin, TN||proposed||—|
|I-169||1.50||2.41||I-69E/US 77/US 83 in Olmito||Port of Brownsville main entrance in Brownsville||2015||current||Currently under construction; partially open and co-signed with SH 550|
|I-369||3.50||5.63||Tenaha||Texarkana, Texas||2013||current||Partially completed in 2013|
|I-270||5.31||8.55||I-25/US 36 at Welby||I-70/US 36 at Denver||1965||current|
|I-470||—||—||Beltway around Denver Metro||—||—||Now part of Colorado State Highway 470|
|I-270||50.59||81.42||I-55/I-255 in Mehlville, MO||I-55/I-70 near Troy, IL||1956||current|
|I-470||13.72||22.08||I-70 in Topeka||I-70/Kan. Tpk. in Topeka||1960||current|
|I-670||2.81||4.52||I-70 in Kansas City, KS||I-70 in Kansas City, MO||1968||current|
|I-270||32.60||52.46||I-70 near Frederick||I-495 north of Bethesda||1975||current|
|2.10||3.38||I-270 east of Potomac||I-495 northwest of Bethesda||1975||current||Serves as an alternate connector for Virginia Travelers.|
|I-370||2.54||4.09||I-270 in Gaithersburg||MD 200 in Derwood||1988||current|
|I-170||11.17||17.98||I-64/US 40 in Richmond Heights||I-270 in Hazelwood||1956||current|
|I-470||16.72||26.91||I-49/I-435 in Kansas City, MO||I-70 in Independence, MO||1983||current|
|I-270||54.97||88.47||Beltway around Columbus||1964||current|
|I-470||6.69||10.77||I-70 near Blaine, OH||I-70 in Elm Grove, WV||1976||current|
|I-670||9.37||15.08||I-70 in Columbus||I-270 near John Glenn Columbus International Airport||2003||current|
|I-271||46.06||74.13||I-71 near Medina, OH||I-90 in Willoughby Hills, OH||1964||current|
|I-471||5.75||9.25||I-275 near Newport, KY||I-71 in Cincinnati, OH||1981||current|
|I-172||19.69||31.69||I-72 in Quincy, IL||US 24 in Quincy, IL||1995||current|
|I-474||14.88||23.95||I-74 in Peoria, IL||I-74 in Morton, IL||1973||current|
|I‑274||—||—||—||—||proposed||—||Proposed route in Winston-Salem|
|I-175||1.44||2.32||I-275 in St. Petersburg, FL||SR 687 in St. Petersburg, FL||1980||current|
|I-275||60.64||97.59||I-75 near Memphis||I-75 in Wesley Chapel||1973||current|
|I-375||1.34||2.16||I-275 in St. Petersburg||US 92 in St. Petersburg||1979||current|
|I‑175||—||—||U.S. Route 82 in Albany||I-75 in Cordele||—||—||Now part of State Route 300|
|I‑475||15.83||25.48||I-75 in Macon||I-75 in Macon||1965||current|
|I‑575||30.97||49.84||I-75 in Kennesaw||SR 5 west of Nelson||1985||current|
|I‑675||11.04||17.77||I-75 in Stockbridge, GA||I-285 southeast of Atlanta, GA||1987||current|
|I-275||83.71||134.72||Beltway around Cincinnati, OH||1962||current||Runs through Indiana, Ohio and Kentucky; I-75 does not run through Indiana|
|I-275||35.01[a]||56.34||I-75 near Monroe, MI||I-96, I-696 & M-5 in Farmington Hills||1977||current|
|I-375||1.06||1.71||BS I-375 in Detroit, MI||I-75 in Detroit, MI||1964||current|
|I-475||16.99||27.34||I-75 near Grand Blanc, MI||I-75/US 23 near Mount Morris, MI||1973||current||Runs east and north of Flint, MI|
|I-675||7.72||12.42||I-75/US 23 near Saginaw, MI||I-75/US 23 near Zilwaukee, MI||1971||current|
|I-475||20.37||32.78||I-75 in Perrysburg||I-75 in Toledo||1964||current|
|I-675||26.53||42.70||I-75 near Miamisburg||I-70 near Medway||1987||current|
|I-175||—||—||I-75 in Chattanooga||I-75 in Lexington||—||—|
|I-275||2.98||4.80||I-40 in Knoxville||I-75/I-640 in Knoxville||1982||current|
|I-475||—||—||I-40/I-75 near Knoxville||I-75 near Knoxville, TN||—||—||Cancelled|
|I-676||6.90||11.10||I-76/US 30 in Philadelphia||I-76 in Camden, NJ||1991||current|
|I-176||11.33||18.23||I-76/Penna Tpk. in Morgantown||US 422 near Reading||1964||current|
|I-276||32.65||52.55||I-76 in King of Prussia||Delaware River bridge (Pennsylvania-NJ state line)(current)
I-95/I-295 in Bristol Township (future)
|I-376||78.70||126.66||I-80 near Hermitage||I-76/US 22 in Monroeville||1972||current|
|I-476||129.61||208.59||I-95 near Chester, PA||I-81 near Clarks Summit, PA||1992||current||Longest Auxiliary Interstate in the country|
|I-576||—||—||—||—||proposed||—||Proposed Southern Beltway route from Pittsburgh International Airport to I-376|
|I‑277||4.46||7.18||Beltway around uptown Charlotte, NC||1981||current|
|I-277||4.14||6.66||I-76 in Akron||I-77 in Akron||1970||current|
|I-278||35.62||57.32||US 1/9 in Linden, New Jersey||Bruckner Interchange in Bronx, New York||1961||current|
|I-478||2.14||3.44||I-278 in Brooklyn, New York||NY 9A in Manhattan, New York||1971||current||Unsigned|
|I-678||14.33||23.06||John F. Kennedy International Airport in Queens, New York||Bruckner Interchange in Bronx, New York||1965||current|
|I-878||0.70||1.13||I-678 in Queens, New York near JFK Airport||JFK Expressway in Queens, New York near JFK Airport||1970||current||Unsigned|
|I-279||13.32||21.44||I-376/US 22/US 30 in Pittsburgh||I-79 in Franklin Park||1972||current|
|I-579||1.57||2.53||PA 885 in Pittsburgh||I-279/PA 28 in Pittsburgh||1962||current|
|I-180||—||—||US 101 in San Rafael||I-80 near Berkeley||1978||1991||Temporary designation of what was formerly part of SR 17, now part of I-580.|
|I-280||57.22||92.09||I-680/US 101 in San Jose||King Street in San Francisco||1964||current|
|I-380||1.671||2.689||I-280 in San Bruno||US 101||1964||current|
|I-480||—||—||I-80 in San Francisco||Sansome Street in San Francisco||1957||1968||Was to be the Embarcadero Freeway; downgraded to a state highway in 1968 and fully decommissioned in 1991|
|I-580||75.63||121.71||US 101 in San Rafael||I-5 near Westley||1964||current||Segments were originally part of I-5W|
|I-680||70.52||113.49||I-280/US 101 in San Jose||I-80 in Cordelia||1955||current||Originally SR 21|
|I-780||6.50||10.46||I-80 in Vallejo||I-680 in Benicia||1955||current||Originally part of I-680|
|I-880||47.22||75.99||I-280/SR 17 in San Jose||I-80/I-580 in Oakland||1983||current||Originally part of SR 17|
|I-880||—||—||—||—||1971||1983||Now part of Interstate 80|
|I-980||2.03||3.27||I-880 in Downtown Oakland||I-580/SR 24 in Oakland||1981||current|
|I‑580||30.09||48.43||US 50 in Carson City||I-80 in Reno||2012||current||Runs concurrently with US 395|
|I-180||13.19||21.23||IL 26/IL 71 in Hennepin, Illinois||I-80 near Princeton, Illinois||1969||current|
|I-280||26.98||43.42||I-80 near Davenport, IA||I-74/I-80 near Colona, IL||1990||current|
|I-380||73.05||117.56||I-80 near Iowa City||US 218 in Waterloo||1985||current||Connects Cedar Rapids with I-80|
|I-480||4.90||7.89||I-80/US 75 in Omaha, NE||I-29/US 6 in Council Bluffs, IA||1966||current|
|I-680||42.86||68.98||I-80 in Omaha, NE||I-80 near Neola, IA||1966||current|
|I-180||3.18||5.12||US 34 (9th St. / 10th St.) in Lincoln||I-80 / US 34 / US 77 in Lincoln||1965||current|
|I-280||—||—||—||—||1958||1965||Now designated as I-680|
|I-580||1.60||2.57||I-480 in Omaha||Lake Street in Omaha||1976||1982||Now part of US 75|
|I-280||17.85||28.73||I-80 in Parsippany-Troy Hills||I-95/NJ Tpk. in Kearny||1958||current|
|I-280||12.41||19.97||I-75 in Toledo, OH||I-80/I-90/Ohio Tpk. in Lake Township, OH||1959||current|
|I-380||—||—||I-76/I-77 in Akron, OH||I-271 in Macedonia, OH||proposed||—|
|I-480||41.77||67.22||I-80/Ohio Tpk. in North Ridgeville, OH||I-80/Ohio Tpk. in Streetsboro, OH||1971||current|
|I-680||16.43||26.44||I-76/Ohio Tpk. in North Lima, OH||I-80/SR 11 near Mineral Ridge, OH||1964||current|
|I-180||28.85||46.43||US 15/US 220 in Williamsport, PA||I-80/PA 147 near Milton, PA||1984||current|
|I-180||—||—||—||—||—||—||Now part of I-176|
|I-280||—||—||—||—||1958||1964||Now part of Pennsylvania Turnpike|
|I-380||24.76||39.85||I-80 in Tunkhannock Township. PA||I-81/I-84/US 6 in Dunmore, PA||1973||current|
|I-480||—||—||—||—||—||—||Now part of Interstate 476|
|I-180||1.09||1.75||I-80 in Cheyenne, WY||I-80 Bus/US 30 in Cheyenne, WY||1984||current||Not built to Interstate Highway standards|
|I-481||15.04||24.20||I-81 in Onondaga, NY||I-81/NY 481 in North Syracuse||1970||current|
|I-781||4.30||6.92||I-81 in Pamelia, NY||Fort Drum main gate in Le Ray, NY||2012||current|
|I-381||1.67||2.69||SR 381 in Bristol||I-81 in Bristol||1961||current|
|I-581||6.64||10.69||US 220/SR 24 in Roanoke||I-81 near Hollins||—||—|
|I‑182||15.19||24.45||I-82/US 12 near Richland||US 12/US 395 in Pasco||1986||current|
|I-283||2.91||4.68||I-76/Penna Tpk. near Highspire||I-83/US 322/Capital Beltway near Harrisburg||1972||current|
|I-384||8.20||13.20||I-84/US 6 in East Hartford||US 6/US 44 in Bolton||1984||current|
|I-684||28.47||45.82||I-287 near White Plains, NY||NY 22 near Brewster, NY||1974||current||Also crosses into Connecticut|
|I-184||3.62||5.83||I-84 in Boise, ID||US 20/US 26||1990||current|
|I-685||14.00||22.53||I-65 in downtown Montgomery, AL||I-85 in Montgomery, AL||proposed||—|
|I‑185||49.30||79.34||US 27/US 280/SR 520 in Columbus||I-85 near LaGrange||1979||current|
|I‑285||63.98||102.97||Beltway around Atlanta, GA||1969||current|
|I‑485||5.9||9.5||I-75/I-85 in Atlanta||I-85 in Atlanta||1964||1975||Now Freedom Parkway, was planned to relive traffic along Downtown Connector (I-75/85) through downtown Atlanta.|
|I‑985||24.04||38.69||I-85 near Buford, GA||SR 369 near Gainesville||1985||current|
|I‑285||—||—||I-85/I-85 Bus./US 29/US 52/US 70 near Lexington, NC||I-40/US 52/US 311/NC 8 in Winston-Salem, NC||proposed||—|
|I‑485||66.68||107.31||Beltway around Charlotte, NC||1988||current|
|I‑785||2.21||3.56||I-40/I-85/I-840/I-85 Bus. in Greensboro, NC||US 70 in Greensboro, NC||2013||current||Future northern terminus at US 29/US 58/US 360/US 58 Bus. in Danville, VA|
|I-185||17.70||28.49||I-385 near Mauldin, SC||US 29 in Greenville, SC||1955||current|
|I-385||42.16||67.85||I-26 near Clinton, SC||US 276 in Greenville, SC||1962||current|
|I-585||2.25||3.62||US 176/US 221/SC 9 in Spartanburg, SC||I-85 Bus./US 176 near Spartanburg, SC||1962||current|
|I-287||98.72||158.87||I-95/NJ Tpk. in Edison, NJ||I-95 in Rye, NY||1961||current|
|I-587||1.21||1.95||I-87/Thruway/NY 28 in Kingston, NY||NY 28/NY 32 in Kingston, NY||1960||current|
|I‑587||—||—||Future I-87 (current US 64) near Zebulon, NC||US 264 near Greenville, NC||proposed||—|
|I-787||10.16||16.35||I-87/Thruway in Albany, NY||NY 7 in Green Island, NY||1968||current|
|I-189||1.49||2.40||US 7 in South Burlington, VT||I-89 in South Burlington||1980||current|
|I-190||3.07||4.94||O'Hare International Airport in Chicago, IL||I-90 in Chicago, IL||1978||current|
|I-290||29.84||48.02||I-90/IL 53 in Rolling Meadows, IL||I-90/I-94/Congress Parkway in Chicago, IL||1972||current|
|I-490||—||—||I-294||I-90||proposed||—||Proposed route number for the O'Hare West Bypass|
|I‑190||19.26||31.00||I-290 in Worcester, MA||Route 2 in Leominster, MA||1983||current|
|I‑290||20.16||32.44||I-395 in Auburn, MA||I-495 in Marlborough, MA||1970||current|
|I-190||28.34||45.61||I-90/Thruway in Cheektowaga, NY||Highway 405 at Lewiston, NY||1959||current|
|I-290||9.80||15.77||I-190 in Tonawanda, NY||I-90/Thruway in Williamsville, NY||1964||current|
|I-390||76.06||122.41||I-86/NY 17 in Avoca, NY||I-490 in Gates, NY||1973||current|
|I-490||37.40||60.19||I-90/Thruway in Bergen, NY||I-90/Thruway in Victor, NY||1970||current|
|I-590||5.31||8.55||I-390 in Brighton, NY||I-490/NY 590 in Rochester, NY||1980||current|
|I-690||14.19||22.84||I-90/Thruway/NY 690 in Van Buren, NY||I-481 in East Syracuse, NY||1962||current|
|I-790||2.41||3.88||I-90/Thruway in Deerfield, NY||NY 5A/NY 55 in Utica, NY||1961||current|
|I-890||9.35||15.05||I-90/Thruway in Rotterdam, NY||I-90/Thruway in Guilderland, NY||1962||current|
|I-990||6.35||10.22||I-290 in Amherst, NY||NY 263 near Lockport, NY||1985||current||Highest numbered Interstate in the Interstate system|
|I-490||2.43||3.91||I-71/I-90 in Cleveland, OH||East 55th Street in Cleveland, OH||1990||current|
|I-190||1.72||2.77||I-90 in Rapid City, SD||US 16 in Rapid City, SD||1962||current|
|I-291||6.02||9.69||I-91 in Windsor, CT||I-84 in Manchester, CT||1994||current|
|I-691||8.38||13.49||I-84 at the Southington-Cheshire town line, CT||I-91 in Meriden, CT||1988||current|
|I‑291||5.44||8.75||I-91 in Springfield, MA||I-90/Mass Pike in Chicopee, MA||1972||current|
|I‑391||4.46||7.18||I-91 in Chicopee, MA||High Street in Holyoke, MA||1970||current|
|I‑293||11.18||17.99||I-93/NH 101 in Manchester, NH||I-93/Everett Tpke in Hooksett, NH||2008||current|
|I‑393||4.60||7.40||I-93 in Concord, NH||NH 9 in Pembroke, NH||1979||current|
|I-294||53.42||85.97||I-80/I-94 in South Holland, Illinois||I-94 in Deerfield, Illinois||1968||current|
|I-194||3.38||5.44||I-94 in Battle Creek. MI||M-66 in Battle Creek, MI||1961||current|
|I-394||9.75||15.69||I-494/US 12 in Minnetonka, MN||4th Street in Minneapolis, MN||1991||current|
|I-494||42.94||69.11||I-94/I-694 in Maple Grove, MN||I-94/I-694 in Woodbury, MN||1985||current||Western and southern half of the Minneapolis–St. Paul beltway|
|I-694||22.62||36.40||I-94/I-494 in Maple Grove, MN||I-94/I-494 in Woodbury, MN||1970||current||Northern and eastern half of the Minneapolis–St. Paul beltway|
|I-194||1.20||1.93||McKenzie Drive near Bismarck, ND||I-94 near Mandan, ND||—||—||Unsigned|
|I-794||3.75||6.04||I-43/I-94 in Milwaukee, WI||WIS 794 in Milwaukee, WI||1980||current|
|I-894||4.70||7.56||I-94 in Milwaukee, WI||I-43/I-94 in Milwaukee, WI||1966||current|
|I-395||54.69||88.02||I-95 in East Lyme, CT||I-290 in Auburn, MA||1983||current|
|I-295||73.77||118.72||I-95/I-495 in New Castle, DE||I-95/US 1 in Lawrence Township, NJ||1994||current|
|I-495||11.47||18.46||I-95/I-295 in Newport, DE||I-95 in Lower Chichester Township, PA||1977||current|
|I-895||—||—||—||—||1979||1980||Now part of I-95|
|I‑395||13.39||21.55||I-95/I-495 in Springfield, VA||US 50 in Washington, DC||1977||current||Original route of I-95 that was proposed to continue through Washington, DC|
|I‑495||31.41||50.55||Beltway around Washington, DC||1961||current||Capital Beltway; runs through Virginia, Maryland and a small sliver of Washington, DC, over the Wilson Bridge|
|I‑695||2.00||3.22||I-395 in Washington, DC||I-295 in Washington, DC||1958||current|
|I-195||4.42||7.11||I-95/SR 112 in Miami, FL||SR 905 in Miami Beach, FL||1961||current|
|I-295||61.04||98.23||Beltway around Jacksonville||1970||current|
|I-395||1.29||2.08||I-95||MacArthur Causeway at Watson Island, Miami, FL||1971||current|
|I-595||12.86||20.70||I-75/SR 869 in Weston, FL||US 1 in Fort Lauderdale, FL||1990||current|
|I-795||—||—||Interstate 95 south of Jacksonville||I-295 in Jacksonville||proposed||—||Currently under construction; partially open as SR 9B but not yet signed as I-795|
|I‑195||1.55||2.49||I-95/Maine Tpk. in Saco, ME||SR 5 in Saco, ME||1980||current|
|I‑295||53.11||85.47||I-95/Maine Tpk. in Scarborough, ME||I-95/Maine Tpk. in Gardiner, ME||1960||current|
|I‑395||4.99||8.03||I-95/US 2/SR 100 in Bangor, ME||US 1A in Brewer, ME||2008||current|
|I‑495||3.70||5.95||I-95/Maine Tpk. in Portland, ME||I-295/US 1 in Falmouth, ME||2004||current||Unsigned|
|I-195||4.71||7.58||I-95/MD 166 near Catonsville, MD||Baltimore-Washington International Airport||1990||current|
|I-395||1.98||3.19||I-95 in South Baltimore, MD||West Pratt Street in Baltimore, MD||1981||current|
|I-595||19.97||32.14||I-95/I-495/US 50 near Washington, DC||US 50/US 301/MD 70 in Annapolis, MD||2011||current||Unsigned designation for US 50|
|I-695||30.57||49.20||Beltway around Baltimore||1958||current|
|I-795||8.99||14.47||I-695 in Pikesville, MD||MD 140 in Reisterstown, MD||1985||current|
|I-895||11.44||18.41||I-95 near Elkridge, MD||I-95 in Baltimore, MD||1979||current|
|I‑295||8.05||12.96||I-95/I-495 near Forest Heights, MD||I-695 in Washington, DC||1964||current|
|I‑195||44.55||71.70||I-95 in Providence, RI||I-495/Route 25 in Wareham, MA||1958||current|
|I‑295||26.58||42.78||I-95 in Warwick, RI||I-95 in Attleboro, MA||1969||current|
|I‑495||121.56||195.63||I-195/Route 25 in Wareham, MA||I-95 in Salisbury, MA||1957||current|
|I‑695||—||—||I-93 in Roxbury, Boston||I-93 in Charlestown, Boston||1955||1971||Cancelled; was to have been built in connection with a planned alignment of I-95 through downtown Boston|
|I‑895||—||—||Route 37/I-295 in Cranston||I-95/I-295 in Attleboro||1968||1982||Cancelled; would have supplemented Interstate 295 to create a full beltway around Providence.|
|I-195||34.17||54.99||I-295 in Hamilton Township, NJ||Route 34 in Wall Township, NJ||1968||current|
|I-895||—||—||I-295 in Burlington, NJ||I-95 in Bristol, PA||1963||1981||Never built|
|I-295||7.70||12.39||Hillside Avenue (NY 25)/NY 24 in Queens, NY||Bruckner Interchange in the Bronx, NY||1970||current|
|I-495||66.38||106.83||Queens Midtown Tunnel in Manhattan, NY||CR 58 in Riverhead, NY||1958||current|
|I-695||1.40||2.25||I-95 in the Bronx, NY||I-295 in the Bronx, NY||1986||current|
|I-895||1.12||1.80||I-278 in the Bronx, NY||I-95 in the Bronx, NY||1970||2017||Currently designated as NY 895|
|I‑295||—||—||—||—||proposed||—||Planned route around the west side of Fayetteville, NC|
|I‑495||4.10||6.60||I-440/US 64/US 64 Bus in Raleigh, NC||I-540/US 64/US 264 in Knightdale, NC||2013||2017||Now part of Interstate 87|
|I‑795||25.46||40.97||US 70/US 117 in Goldsboro, NC||I-95/US 264 in Wilson, NC||2007||current|
|I-695||—||—||I-95 near Philadelphia International Airport||I-95 in Philadelphia||1964||1977||Never built|
|I-195||3.24||5.21||SR 195 in Richmond, VA||I-64/I-95 in Richmond, VA||1970||current|
|I-295||52.56||84.59||I-95 near Petersburg, VA||I-64 near Short Pump, VA||1980||current|
|I-595||—||—||I-395 near Arlington, VA||U.S. Route 1 at Ronald Reagan Washington National Airport||—||—||Now part of U.S. Route 1.|
|I-895||—||—||I-95 near Richmond||I-295 near Richmond||1996||2002||Currently designated as State Route 895, it was originally planned as a Interstate designation, but did not get approved by AASHTO.|
|I-196||37.07||59.66||US 31 in Norton Shores, MI||I-96/US 16 in Grand Rapids, MI||1959||1963||Now the western end of I-96|
|I-196||80.65||129.79||I-94/US 31 near Benton Harbor, MI||I-96/M-37 in Grand Rapids, MI||1963||current|
|I-296||3.43||5.52||I-196 in Grand Rapids, MI||I-96/M-37 in Walker, MI||1962||current||Unsigned since 1979|
|I-496||11.78||18.96||I-69/I-96 near Lansing, MI||I-96 and US 127 near Lansing, MI||1970||current|
|I-696||29.39||47.30||I-96/I-275 & M-5 in Novi, MI||I-94 in Roseville, MI||1989||current|
- Weingroff, Richard F. (Summer 1996). "Federal-Aid Highway Act of 1956, Creating the Interstate System". Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved March 16, 2012.
- DeSimone, Tony (October 31, 2002). "Interstate Route Numbering". Route Log and Finder List. Federal Highway Administration. Retrieved February 3, 2008.
- Adderly, Kevin (December 31, 2015). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of December 31, 2015". Route Log and Finder List. Federal Highway Administration. Retrieved February 6, 2016.
- Special Committee on U.S. Route Numbering (December 8, 1990). Written at Phoenix. "Report of the Special Committee on U.S. Route Numbering to the Executive Committee" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived (PDF) from the original on October 16, 2017.
- Warring, KS (January 2, 2008). "Interstate 905 Freeway Interchanges" (PDF). California Numbered Exit Uniform System. Sacramento: California Department of Transportation. Retrieved February 5, 2009.
- Cavanaugh, Patricia (October 2006). "Politics and Freeways: Building the Twin Cities Interstate System". University of Minnesota.
- Tennessee Department of Transportation (October 31, 2003). "TDOT Announces Decision on State Route 840 North" (PDF) (Press release). Tennessee Department of Transportation. Archived from the original (PDF) on November 27, 2007. Retrieved July 17, 2007.
- Federal Highway Administration (October 31, 2002). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Retrieved July 8, 2007.
- Dozier, Daniel A. (September 5, 2013). "Request for I-69 Designation for I-164 from I-64 to US 41" (PDF) (Letter). Letter to Richard J. Marquis. Indianapolis: Indiana Department of Transportation. Retrieved January 9, 2015 – via American Association of State Highway and Transportation Officials.
- Highway Information Services Division (December 31, 2013). Highway Location Reference. Maryland State Highway Administration. Retrieved March 2, 2012.
- Montgomery County (PDF)
- Michigan Department of Transportation & Michigan Center for Shared Solutions and Technology Partnerships (2009). MDOT Physical Reference Finder Application (Map). Michigan Department of Transportation. Retrieved February 6, 2016.
- Rand McNally (2008). "Michigan: Cities" (Map). The Road Atlas. 1 in≈5 mi. Chicago: Rand McNally. p. 52. Detroit & Vicinity inset. § I3. ISBN 0-528-93981-5. OCLC 226315010.
- Google (February 24, 2010). "Overview Map of I-275" (Map). Google Maps. Google. Retrieved February 24, 2010.
- "State Seeking Future Interstate Designation for U.S. 264 to Greenville". North Carolina Governor's Office. Retrieved 10 November 2016.
- Mike DeBonis (28 November 2011). "Interstate 695 reappears in D.C". Washington Post.
- Highway Information Services Division (December 31, 2013). Highway Location Reference. Maryland State Highway Administration. Retrieved September 24, 2012.
- Special Committee on U.S. Route Numbering (September 24, 2017). Written at Phoenix. "Special Committee on U.S. Route Numbering" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. p. 4. Retrieved October 21, 2017.