List of intrastate Interstate Highways

The intrastate Interstate Highways in the contiguous United States, highlighted in red, not including Interstates 73 and 99.

There are several intrastate Interstate Highways; that is, Interstate Highways that are located entirely within one state. The concept seems contradictory at first; the word "Interstate" refers to the way the entire group of highways is funded (as a national system of interconnected highways), not to the route each given highway travels.

Within the contiguous 48 states

This list includes only primary Interstate highways (those with route numbers less than 100). Most (but not all) three digit Interstates are intrastate.

Interstate Highway	State	Route	Length (mi)	Length (km)	Notes
04 ! Interstate 4	Florida	Tampa (I-275) to Daytona Beach (I-95)	132.3	212.9
12 ! Interstate 12	Louisiana	Baton Rouge (I-10) to Slidell (I-10/I-59)	85.6	137.8
16 ! Interstate 16	Georgia	Macon (I-75) to Savannah (US-17)	166.8	268.4
17 ! Interstate 17	Arizona	Phoenix (I-10) to Flagstaff (I-40)	145.8	234.6
19 ! Interstate 19	Arizona	Nogales (Mexican border) to Tucson (I-10)	63.4	102.0	Interstate 19 reaches the Mexican border but does not cross any state lines.
27 ! Interstate 27	Texas	Lubbock (US-87) to Amarillo (I-40)	124.1	199.7
37 ! Interstate 37	Texas	Corpus Christi (US-181) to San Antonio (I-35)	143.0	230.1
43 ! Interstate 43	Wisconsin	Beloit (I-39 & I-90) to Green Bay (US-41)	191.6	308.4
45 ! Interstate 45	Texas	Galveston (TX-124) to Dallas (I-30)	284.9	458.5	The only two-digit Interstate ending in 5 or 0 to be an intrastate Highway. Such numbers are supposed to be signed to major interstates, which is why it is unusual that this one is intrastate.
49 ! Interstate 49	Louisiana	Lafayette (I-10) to Shreveport (I-20)	208.3	335.2	Planned to reach Kansas City, Missouri
73 ! Interstate 73	North Carolina	Ellerbe (US-220) to Greensboro (I-40 & I-85)	56.7	91.2	Planned to reach Michigan and South Carolina
86 ! Interstate 86 (west)	Idaho	Heyburn (I-84) to Pocatello (I-15)	62.9	101.2
87 ! Interstate 87	New York	New York City (I-278) to Champlain (Canadian border)	333.5	536.7	The longest intrastate Interstate highway, Interstate 87 reaches the Canadian border, but it does not cross any state lines.
88W ! Interstate 88 (west)	Illinois	Silvis (I-80) to Hillside (I-290)	140.6	226.3
88E ! Interstate 88 (east)	New York	Binghamton (I-81) to Schenectady (I-90)	117.8	189.6
96 ! Interstate 96	Michigan	Muskegon (US 31) to Detroit (I-75)	192.1	309.2
97 ! Interstate 97	Maryland	Annapolis (US-50) to Baltimore (I-695)	17.6	28.3	Currently the shortest two-digit interstate highway in the country, the only two-digit interstate highway on the U.S. mainland located entirely within one county, and the only two-digit interstate highway on the U.S. mainland that does not connect to any other two-digit interstate highways.
99 ! Interstate 99	Pennsylvania	Bedford (I-70/I-76) to Bellefonte (I-80)	85.0	136.8	Interstate 99 may eventually extend through New York via US 15 and Maryland to Interstate 68. Surface roads connect it with the Pennsylvania Turnpike at its current signed south end.[citation needed]

Additionally, there are four Interstate highways that are almost entirely intrastate:

• Interstate 66 is located almost entirely in Virginia, but it has a very short section in the District of Columbia. I-66 is 75 miles in length, with one-half mile in D.C.
• Interstate 72 is located almost entirely in Illinois, but it has a very short section in Missouri. I-72 is 184 miles in length, with 2 miles in Missouri.
• Interstate 76 (western section) is located almost entirely in Colorado, but it has a very short section in Nebraska that connects Interstate 80. I-76 is 186 miles in length, with less than 3 miles in Nebraska.
• Interstate 86 (eastern section) is located almost entirely in New York, but it has a short section in Pennsylvania that connects Interstate 90. I-86 is 177 miles in length (in the process of being expanded to 380 miles), with less than 7 miles in Pennsylvania.

Outside of the contiguous 48 states

As Alaska and Hawaii do not share land borders with any other U.S. state, their Interstate highways are all located fully within their respective state's boundaries. Puerto Rico is not a state; however, it also has highways funded by the Federal Government as Interstate highways.

Signed Interstates

H-1, H-2, and H-3 stand for Hawaii-1, Hawaii-2, and Hawaii-3, respectively. These freeways are part of the Interstate Highway System and are thus called Interstate highways. These are all located on the heavily-populated island of Oahu, and there are none on the other islands.

Interstate Highway	Route	Length (mi)	Length (km)
1 ! Interstate H-1	Kapolei, HI (HI-93) to Honolulu, HI (HI-72)	27.2	43.8
2 ! Interstate H-2	Pearl City, HI (H-1) to Wahiawā, HI (HI-99)	8.3	13.4
3 ! Interstate H-3	Hālawa, HI (H-1) to Marine Corps Base Hawaii	15.3	24.6

Unsigned Interstates

Interstate highways in Alaska and Puerto Rico are not signed as Interstate highways, and are designated as such primarily for purposes of Federal funding. Interstates A-1 through A-4 are located in Alaska, and Interstates PRI-1 through PRI-3 are located in Puerto Rico. These highways are not required to meet interstate standards, and as a result, most portions of these interstate highways are not grade-separate freeways. Freeways in Puerto Rico are primarily toll roads that are not funded through the Eisenhower Interstate System. Very few freeways exist in Alaska; they are located primarily near Anchorage, Fairbanks, and Wasilla.

Interstate Highway	Route	Length (mi)	Length (km)
A1 ! Interstate A-1	Anchorage, AK (A-3) to Canadian border	408.2	656.9
A2 ! Interstate A-2	Tok, AK (A-1) to Fairbanks, AK (A-4)	202.2	325.4
A3 ! Interstate A-3	Anchorage, AK (A-1) to Soldotna, AK	148.1	238.3
A4 ! Interstate A-4	Palmer, AK (A-1) to Fairbanks, AK (A-2)	323.7	520.9
P1 ! Interstate PRI-1	Ponce, PR (PRI-2) to San Juan, PR (PRI-2)	71.1	114.4
P2 ! Interstate PRI-2	Ponce, PR (PRI-1) to San Juan, PR (PRI-3)	138.1	222.3
P3 ! Interstate PRI-3	San Juan, PR (PRI-2) to Ceiba, PR	40.6	65.3