Interstate 15 in Utah

This article is about the section of this freeway in Utah. For the entire length of the freeway, see Interstate 15.

Interstate 15
Route information
Maintained by Utah Department of Transportation (UDOT)
Length	400.592 mi (644.690 km)
NHS	Entire route
Major junctions
South end	I-15 towards Littlefield, Arizona
Major intersections	I-70 near Cove Fort US 50 near Holden and Scipio US 6 in Santaquin and Spanish Fork US 89 in Lehi, Draper, Bountiful, and Farmington I-215 in Murray and North Salt Lake I-80 in South Salt Lake and Salt Lake City I-84 in Riverdale and Tremonton US 91 in Brigham City
North end	I-15 towards Malad, Idaho
Location
Country	United States
State	Utah
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Utah State Highway System Interstate US State Minor Scenic
← SR-14 → SR-16

In the U.S. state of Utah Interstate 15 runs north–south through the southwestern and central portions of the state, passing through many of the population centers of the state, including St. George, Provo, Salt Lake City, and Ogden, the latter three being part of the urban area known as the Wasatch Front. It is the primary north–south highway in Utah, as the majority of the state's population lives along its corridor. The only Metropolitan Statistical Area in Utah not connected by I-15 is the Logan Utah-Idaho Metropolitan Statistical Area.

Route description

The interstate passes through the fast-growing Dixie region, which includes St. George, Cedar City, and eventually most of the major cities and suburbs along the Wasatch Front, including Provo, Orem, Sandy, West Jordan, Salt Lake City, Layton, and Ogden. Around Cove Fort, Interstate 70 begins its journey eastward across the country. The interstate merges with I-80 for about 3 miles (4.8 km) from South Salt Lake to just west of Downtown Salt Lake City and merges with Interstate 84 from Ogden to Tremonton. Along nearly its entire length through the state, I-15 winds its way along the western edge of a nearly continuous range of mountains (including the Wasatch Range in the northern half of the state). The only exceptions are when it passes through the mountains south of Cedar City and again north of Cove Fort.

Southern Utah

Washington County

Interstate 15 near New Harmony, south of Cedar City, looking north.

I-15 begins at the Arizona/Utah border in Washington County and heads north-northeast, continuing with two lanes in each direction. (The two lane configuration continues north until the Wasatch Front in the north central part of the state.) Just past the border there is a port of entry on each side of the freeway. These ports of entry (weigh stations) are jointly operated by the states of Utah and Arizona and are the first northbound exit and last southbound exit on I-15 in Utah. The route turns north as it passes the Bloomington area of city of St. George and an interchange with SR-7 (Southern Parkway) before it crosses the Virgin River. (SR-7 provides access to the new St. George Municipal Airport.) Immediately north of the Virgin River, and partially spanning the Santa Clara River, is the new Dixie Drive interchange. After the interchange with SR-18 (Bluff Street) I-15 turns northeast again and passes the eastern side of downtown St. George, with an interchange with SR-34 (St. George Boulevard). These two interchanges are the southern and northern ends of the St. George I-15 Business Loop. From this point north I-15 generally follows the route of the Old US-91 to the northern border of Utah. (The route of Old US-91, in turn, followed the older Arrowhead Trail highway to Salt Lake City.) After leaving St. George, I-15 continues northeast and passes through the northern part of the city of Washington, with interchanges at 3050 East, Washington Parkway, and SR-9 (State Street). Northeast of Washington I-15 passes through the northwestern side of the town of Leeds, with one-way interchanges on the southwest and northeast ends of town. After passing trough the northwestern part of Toquerville, and an interchange with SR-17, I-15 resumes a more north-northeastern course as it ascends about a 1,000 feet (300 m) higher on the Colorado Plateau. Along the way it passes through the areas of Browse and Pintura, with interchanges at both, as well as two more ranch exits further northeast. After it ascent, it passes by the northwest corner of Zion National Park, with an interchange provide access to the Kolob Canyon are of that national park. Next is an interchange that provides access to New Harmony (several miles west) and Kanarraville (several miles to the northeast). This interchange is also at the border of Washington County and Iron County.

Iron County

Just after entering Iron County, I-15 reaches the southern most rest areas along it route within the state (with one each, northbound and southbound). After passing about a mile west of Kanarraville it reaches an interchange in Fort Hamilton. The freeway then briefly turns nearly east before turning north again to pass through the west side of Cedar City. The first interchange is a the southern end of SR-130 (Main Street) and the Cedar City I-15 Business Loop. Just north is the 200 South (SR-56), which provides access to downtown Cedar City as well as the Cedar City Regional Airport. After this interchange, the freeway turns northeast before the final Cedar City interchange with SR-130 (once again). This interchange is also the northern end of the Cedar City I-15 Business Loop, although no longer indicated so by signage. The freeway then passes by the eastern edge of Enoch, but without an interchange within that city. After an interchange within the area of Summit I-15 heads east-northeast before passing by the northwest edge of Parawon, with interchanges on the west (200 South/SR-143) and north (Main Street/SR-274) sides of town. After Parawon, the freeway curves back to a northeast course as it passes about a mile west of Paragonah and reaching an interchange on the north side of that city (SR-271. Continuing northeast it reaches the next pair of rest areas before and interchange with SR-20 and then a ranch exit (exit 100).

Beaver County

As I-15 enters Beaver County the interstate turns northwest as it winds its way through the mountain pass on it way to the city of Beaver, with two interchanges serving that city.

Millard County

Extinct volcano cone near Fillmore, Utah off I-15.

The road continues in a general north-northeast direction before intersecting with the western terminus of I-70. Past I-70, the route meanders to the north and northeast before straightening out to the northeast southwest of Kanosh. The highway passes the east side of both Meadow and Fillmore and the west side of Holden. The route turns north briefly after bypassing Scipio to the east before turning northeast. Past the interchange with SR-28 (which serves as a connector to I-70 for southbound I-15 motorists),

Juab County

The freeway passes the eastern side of Nephi. The interstate then turns northwest and north, bypassing Mona and Rocky Ridge to the east.

Northern Utah

Utah County

The highway enters the Wasatch Front and the Provo-Orem metropolitan area as it turns northeast and enters the town of Santaquin, where US-6 begins its overlap with I-15. Exiting Santaquin, the highway turns north and then northeast again to enter Payson. Continuing northeast, the route enters Spanish Fork and gains one lane in each direction (the first time the interstate widens in the state). On the north side of Spanish Fork it intersects with US-6, where it turns north and gains one more lane in each direction, plus an additional [High occupancy/toll and express toll lanes|express lane]] in both directions. This interchange also marks the northern end of the overlap with US-6. (The section between Spanish Fork and Lehi was recently rebuilt in 2010-12 as part of the I-15 CORE project.) Continuing north with four lanes, plus an Express Lane, in both directions, the route passes through the far west side of Springville, crossing SR-77 and SR-75, and then turns northwest south of Provo. The highway enters Provo and intersects with the southern terminus of US-189. The route continues northwest, bisecting the west side of Provo. After passing SR-114, it reaches Orem and passes SR-265. Right before the interchange at SR-241, the route turns northwest, entering Lindon. The route then exits Lindon and enters the south side American Fork, meandering between the west-northwest and northwest. The route straightens out the northwest and enters Lehi. In Lehi, US-89 begins an overlap with I-15 and passes SR-92. At this point the freeway narrows to just three lanes, plus and Express Lane, in both directions. Past Lehi, the interstate exits the Provo metropolitan area and Utah County to enter the Salt Lake City metropolitan area.

Salt Lake County

I-15 in Salt Lake City

As the route enters the Salt Lake Valley from only one of three other points connecting Salt Lake County and Utah County (the others being SR-68 and Traverse Ridge Road), it turns northeast. Past SR-140 turns north. The route enters Draper and turns north-northwest past SR-71, where US-89 ends its overlap with the interstate. As it enters Sandy, the interstate widens to five lanes past SR-151. The route straightens out to the north. The route turns north-northwest past SR-209 and soon after enters Midvale. The route intersects I-215, a beltway running through many of Salt Lake City's suburbs, in Murray. Past this interchange, the route heads north and enters Murray. The route exits Murray and enters South Salt Lake, where an interchange with I-80 and SR-201 is located. The southern overlap of I-80 begins at this point. Also at this point, the highway enters Salt Lake City and a collector/distributor road begins at either side of the interstate, providing an exit to SR-201, 1300 South, and SR-270. After the collector-distributor ends, the route turns northwest to bypass downtown Salt Lake City. The route turns north after SR-269 and the northern end of the I-80 overlap. Past this point, the HOV lane ends and the highway loses one lane in each direction. Past the single-point urban interchange at SR-268, the interstate turns northwest and loses another lane. Before US-89, the road turns northeast briefly before turning north and entering Davis County.

An 80 mph speed limit sign in one of the test zones.

Davis and Weber counties

The road enters North Salt Lake and I-215 defaults onto I-15 northbound. The route then gains two lanes in each direction and turns northeast. Past 2600 South, the highway turns north and enters Woods Cross to the west and Bountiful to the east. In West Bountiful, US-89 begins another overlap with I-15. The highway continues north and enters Centerville. The route exits Centerville and enters Farmington and turns northwest, US-89 exiting on its own separate freeway at an interchange (where the Legacy Parkway terminates). The route passes through Kaysville, Layton, and Clearfield before turning north, passing the west side of Hill Air Force Base. The road continues north through Sunset before turning northeast through Roy. The interstate exits Davis County and enters Weber County. In Roy, I-84 defaults onto I-15 northbound and an overlap begins. The highway enters Ogden, with the Ogden-Hinckley Airport located on the west side of the freeway. Past the airport, the route turns northwest before exiting Ogden and entering Marriott-Slaterville, where it straightens out to the north. Past Farr West, the freeway turns northwest briefly before turning north and exiting Weber County, the Ogden-Clearfield metropolitan area, and the Wasatch Front.

Box Elder County

I-15 warning sign for potentially drowsy drivers

The interstate continues north through Box Elder County. Brigham City, the county seat, is bypassed to the west by the freeway. Past US-91 (which continues to Logan and points northward), the route turns northwest to Tremonton, where I-84 separates, continuing northwest to Snowville, and I-15 turns north. The freeway continues in this general direction until the Idaho border. The last exit northbound is located at exit 398, 25800 North, which provides a connection to the town of Portage.

History

See also: U.S. Route 91

The southwest-north alignment followed by I-15 was a major transportation corridor in the early 20th century, followed by auto trails such as the Arrowhead Trail (south from Salt Lake City), Evergreen National Highway (entire length), and Banff-Grand Canyon Road (north from Nephi). In 1926, when the numbered system of U.S. highways was created, this route was signed U.S. Route 91

Legislative designation for I-15 within Utah, until 1977

The route of I-15 from St. George to Brigham City was built along the corridor of what was U.S. Route 91 from 1926-1974. In 1974 I-15 was reasonably intact and US-91 was deleted, with the unfinished segments signed as Temporary I-15. The route north of Brigham City was built along the corridor of an old route of U.S. Route 191. This highway was also deleted once I-15 was reasonably intact. However, a different route in Utah was re-designated US-191 in 1982.

Prior to 1977 the route of I-15 (and US-91 before) was also designated State Route 1 by the state of Utah, but no portion of the route was signed with this number.

In January 2009, the speed limit on two sections of I-15 together totaling 34 miles was raised to 80 mph as a "test," making Utah the second state to currently have speed limits greater than 75 mph. Since that time additional sections with higher speed limits have been added within Utah.

Exit list

County	Location	mi	km	Old exit	New exit	Destinations	Notes
Washington	St. George	2.135	3.436	2	2	SR-7 east (Southern Parkway) – St. George Municipal Airport
		4.641	7.469	4	4	Brigham Road
		5.619	9.043		5	Dixie Drive
		6.309	10.153	6	6	I-15 BL north / SR-18 north (Bluff Street) – Santa Clara
		8.652	13.924	8	8	I-15 BL south / SR-34 west (St. George Boulevard) – Dixie State University, SR-18
	Washington	10.910	17.558	10	10	SR-212 east (Green Springs Drive)
		13.386	21.543	13	13	Washington Parkway
	Washington–Hurricane line	15.888	25.569	16	16	SR-9 east (State Street) – La Verkin, Zion National Park
	Leeds	22.579	36.337	22	22	SR-228 northeast (Main Street) – Silver Reef	Northbound exit and southbound entrance
		23.703	38.146	23	23	SR-228 northeast-southwest (Silver Reef Road) – Silver Reef	Southbound exit and northbound entrance
	Toquerville	27.470	44.209	27	27	SR-17 south / SR-228 southwest – Leeds, La Verkin, SR-9, Zion National Park
	​	30.682	49.378	30	30	Browse
	​	31.861	51.275	31	31	Pintura
	​	33.435	53.808	33	33	Ranch exit (Snowfield)
	​	36.763	59.164	36	36	Ranch exit (Black Ridge)
	​	40.253	64.781	40	40	Kolob Canyons (Zion National Park)
	​	42.159	67.848	42	42	New Harmony, Kanarraville	Former SR-58 (north-northwest) & former SR-144 (west)
Iron	​	51.149	82.316	51	51	Hamilton Fort, Kanarraville	Former SR-58 (south)
	Cedar City	56.787	91.390	57	57	I-15 BL north / SR-130 north (South Main Street) – SR-14, Cedar Breaks National Monument, SR-56
		58.837	94.689	59	59	SR-56 east-west (200 North) – SR-130, Cedar City Regional Airport
		62.497	100.579	62	62	I-15 BL south (North Main Street) / SR-130 north-south – Enoch, Minersville, SR-56 & SR-14, Cedar Breaks National Monument	Exit no longer signed as I-15 Business Loop
	​	70.263	113.077	71	71	Summit, Enoch	Former SR-38
	Parowan	75.183	120.995	75	75	I-15 BL north (200 South) / SR-143 south
		77.801	125.209	78	78
	​	82.253	132.373	82	82	SR-271 south (Main Street) – Paragonah
	​	94.453	152.007	95	95	SR-20 east – US 89, Panguitch, Kanab, Circleville
	​	99.690	160.436	100	100	Ranch exit (Fremont Road)
Beaver	​	108.745	175.008	109	109	I-15 BL north (Main Street) / SR-160 – SR-21, SR-153, Milford, Junction
	Beaver	111.780	179.892	112	112	I-15 BL south (1400 North) / SR-160 – SR-21, SR-153, Milford, Junction
	​	120.126	193.324	120	120	Manderfield
	​			125	125	Ranch exit	Exit closed
	​	129.438	208.310	129	129	Sulphurdale
Millard	​	132.170	212.707	132	132	I-70 east – Richfield, Denver
	​	134.875	217.060	135	135	Historic Cove Fort (SR-161)
	​	138.073	222.207	138	138	Ranch exit
	​	146.493	235.758	146	146	Kanosh	Former SR-133
	Meadow	158.265	254.703	158	158	SR-133 – Kanosh
	Fillmore	163.370	262.919	163	163	I-15 BL north (SR-99)
		166.723	268.315	167	167	I-15 BL south (SR-99)
	​	173.507	279.232	174	174	SR-64 north to US 50 west – Holden, Delta
	​	178.330	286.994	178	178	US 50 west – Holden, Delta	South end of US-50 overlap
	​	183.638	295.537	184	184	Ranch exit
	​	188.439	303.263	188	188	US 50 east – Scipio	North end of US-50 overlap
Juab	​	202.189	325.392	202	202	Yuba Lake
	​	206.553	332.415	207	207	Mills, Levan (SR-78)
	Nephi	222.812	358.581	222	222	I-15 BL north to SR-28 – Salina, Richfield
		225.248	362.502	225	225	SR-132 – Ephraim, Manti, Delta
	​	228.065	367.035	228	228	I-15 BL south (SR-28) – Nephi
	​	233.161	375.236	233	233	SR-54 – Mona
Utah	Santaquin	242.447	390.181	245	242	South Santaquin
		244.788	393.948	248	244	US 6 west – Eureka, Delta	South end of US-6 overlap
	Payson	248.829	400.451	252	248	Payson, Salem (SR-178)
		250.923	403.821	254	250	SR-115 – Payson, Benjamin
	​	253.557	408.060	256	253	SR-164 – Spanish Fork, Benjamin
	Spanish Fork	257.264	414.026	260	257	SR-156
		257.636	414.625	261	258	US 6 east to US 89 – Price, Manti	North end of US-6 overlap; northbound exit is via exit 257
	Springville	259.976	418.391	263	260	SR-77
		261.821	421.360	265	261	SR-75 – Provo
	Provo	263.373	423.858	266	263	US 189 north (University Avenue)Module:Jct warning: "road" parameter is deprecated
		265.589	427.424	268	265	SR-114 (Center Street) – Provo Municipal Airport	Signed as exits 265A (east) and 265B (west) northbound
	Orem	269.072	433.029	272	269	SR-265 (University Parkway)
		270.660	435.585	274	271	Center Street
		271.670	437.210	275	272	SR-52 (800 North) to US 189
	Lindon	272.767	438.976	276	273	1600 North (SR-241)
	Pleasant Grove	275.328	443.097	278	275	Pleasant Grove, Lindon	Near the Sam White Bridge
	American Fork	276.501	444.985	279	276	500 East (SR-180) – Pleasant Grove
		278.586	448.341	281	278	Main Street (SR-145)
	Lehi	279.701	450.135	282	279
		282.311	454.336	285	282		South end of US-89 overlap
		283.985	457.030	287	284	SR-92 – Highland, Alpine
Salt Lake	Draper	288.272	463.929	291	288	SR-140 (14600 South)
		289.832	466.439	293	289	SR-154 (Bangerter Highway)
		291.358	468.895	294	291	US 89 north / SR-71 (12300 South)	North end of US-89 overlap
	Sandy	292.612	470.913		292	SR-175 (11400 South)	Opened late 2010
		293.634	472.558	297	293	SR-151 (10600 South)
		295.616	475.748	298	295	SR-209 (9000 South)
	Midvale	297.920	479.456	301	297	SR-48 (7200 South)
	Murray	299.005	481.202	302	298	I-215 (Belt Route)
		300.300	483.286	303	300	SR-173 (5300 South)
		301.653	485.463	304	301	SR-266 (4500 South)
	South Salt Lake	303.414	488.298	306	303	SR-171 (3300 South)
		304.691	490.353	307	304	I-80 east – Cheyenne	South end of I-80 overlap Part of the "Spaghetti Bowl" interchange
		305.231	491.222	308A	305A	SR-201 west – West Valley	Part of the "Spaghetti Bowl" interchange
		305.198	491.169	308B	305B	2100 South (SR-201)
	Salt Lake City	306.315	492.966	309A	305C	1300 South
		306.607	493.436	309B	305D	900 South (SR-270)	Northbound exit and southbound entrance
		307.500	494.873	310	306	600 South (SR-269)	Northbound exit and southbound entrance
		307.740	495.260	310	307	400 South	Northbound exit and southbound entrance are HOV-only
		308.079	495.805	311	308	I-80 west – Salt Lake City International Airport, Reno, Nevada	North end of I-80 overlap
		309.333	497.823	312	309	600 North (SR-268)
		310.239	499.281	313	310	1000 North	No northbound exit
		311.792	501.781	314	311	2300 North/Warm Springs Road
		311.947	502.030	315	312	US 89 south (Beck Street)	Southbound exit and northbound entrance
Davis	North Salt Lake	313.128	503.931	315	312	US 89 north	Northbound exit and southbound entrance
		313.275	504.167	316	313	I-215 south (Belt Route) – Salt Lake City International Airport	Southbound exit and northbound entrance
		314.301	505.818	317	314	Center Street	Southbound exit only
	North Salt Lake–Woods Cross line	315.243	507.334	318	315	2600 South (SR-93)
	Woods Cross–Bountiful– West Bountiful tripoint	316.870	509.953	320	316	SR-68 (500 South)
	West Bountiful	317.557	511.058	321	317	400 North (SR-106)	Northbound exit and southbound entrance
	West Bountiful–Bountiful line	318.024	511.810	321	317	US 89 south	South end of US-89 overlap; southbound exit and northbound entrance
	Centerville	319.512	514.205	322	319	Centerville (SR-105)
	Farmington	322.916	519.683	325	322	SR-227Module:Jct warning: "road" parameter is deprecated	Northbound exit and southbound entrance
		324.026	521.469	326	324	US 89 north to I-84 east – South Ogden	North end of US-89 overlap; northbound exit and southbound entrance
		324.243	521.819		324	Legacy Parkway (SR-67)	Southbound exit and northbound entrance
		324.741	522.620	327	325	SR-225Module:Jct warning: "road" parameter is deprecated	Northbound exit is via exit 324
	Kaysville	328.640	528.895	331	328	SR-273
	Layton			332	330	I-15 BL (Main Street/Fort Lane) / SR-126 north	Northbound exit and southbound entrance Exit closed upon completion of Layton Parkway interchange (same exit number, but further north) Business loop eliminated upon move
		330.019	531.114	332	330	SR-126 north (Layton Parkway)
		331.589	533.641	334	331	SR-232 (Hill Field Road) – Hill Air Force Base
		332.883	535.723	335	332	SR-108 (Antelope Drive) – Antelope Island
	Clearfield	334.066	537.627	336	334	SR-193 (700 South)
		335.800	540.418	338	335	SR-103 (650 North) – Hill Air Force Base
Weber	Roy	338.447	544.678	341	338	SR-97 (5600 South) – Hill Air Force Base
	Riverdale	339.133	545.782	342	339	SR-26 (Riverdale Road) to I-84 east	Northbound exit and southbound entrance
		340.227	547.542	343	340	I-84 east – Riverdale, Cheyenne	South end of I-84 overlap; northbound exit is via exit 339
	Ogden	341.948	550.312	344	341	SR-79 (31st Street)
		343.067	552.113	345	342	SR-53 (24th Street)	Northbound exit and southbound entrance
	West Haven	343.852	553.376	346	343	SR-104 (21st Street, Wilson Lane) to Ogden City Center
	Marriott-Slaterville	344.968	555.172	347	344	SR-39 (12th Street)
		346.726	558.001	349	346	400 North
	Farr West	349.361	562.242	352	349	SR-134 (2700 North)
Box Elder	​	351.853	566.253	354	351	SR-126 to US 89 – Willard, Pleasant View
	Willard	357.554	575.427	360	357	SR-315 – Perry
		358.566	577.056	361		Port of Entry
		360.542	580.236	363		Rest Area	Northbound exit and entrance
		362.020	582.615	364	362	US 91 (1100 South Street, I-15 Bus. north, I-84 Bus. west) to US 89
	Brigham City	363.738	585.380	366	363	Forest Street
		365.508	588.228	368	365	SR-13 (900 North Street, I-15 Bus. south, I-84 Bus. east)
	Honeyville	372.734	599.857	375	372	SR-240 to SR-13 – Bear River
	Tremonton	376.532	605.970	379	376	SR-13 (I-15 Bus. north, I-84 Bus. west) – Garland, Bear River
	​	379.334	610.479	382	379	I-84 west (SR-30 west) – Tremonton, Boise	North end of I-84 overlap; south end of SR-30 overlap
	Tremonton	381.037	613.220	383	381	I-15 BL south – Garland
	​	385.266	620.026	387	385	SR-30 east – Riverside, Logan	North end of SR-30 overlap
	​	392.387	631.486	394	392	SR-13 south – Plymouth
	​	398.817	641.834	402	398	Portage	Former SR-90
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

External links

Template:Attached KML/Interstate 15 in Utah

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