Interstate 15 in Utah - Route Description

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 (5 km) from South Salt Lake to just west of Downtown Salt Lake City and also 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 (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.

I-15 begins at the Arizona/Utah border and heads northeast, continuing with two lanes in each direction. Right past the border, there is a port of entry on each side, making the first exit on the interstate in Utah going northbound. The route turns north past Bloomington before turning northeast again after the interchange with SR-18 to pass the eastern side of St. George. The highway continues northeast after exiting St. George and turns north-northeast north of Toquerville. South of Cedar City, the route turns east and north to pass through the west side of Cedar City and turns northeast again. Past a ranch exit (exit 100), the interstate turns northwest and then north to enter the western side of Beaver, with two interchanges serving that town. 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), the road passes the eastern side of Nephi. The interstate then turns northwest and north, bypassing Mona to the east.

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 intersects with US-6 on the north side of town, where it turns north and gains one lane in each direction, the first time the interstate widens in the state. This interchange also marks the northern end of the overlap with US-6. The route passes the west side of Springville and turns northwest south of Provo. The highway enters Provo and intersects with the southern terminus of US-189. Past this point, the interstate widens to four lanes in each direction. The route continues northwest, bisecting the west side of Provo. Past SR-114, the road loses one lane in each direction. Past SR-265, the highway once again widens to four lanes in each direction and gains an HOV lane begins. The lane gain is temporary and when the route turns north, the fourth lane is lost. At this point, the highway exits Provo and enters Orem. 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. Past Lehi, the interstate exits the Provo metropolitan area and Utah County to enter the Salt Lake City metropolitan area.

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, the highway widens to four lanes in each direction (not including the HOV lane) and 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, colloquially known as the "Spaghetti Bowl". 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.

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 and the Ogden-Hinckley Airport is located on the west side of the highway. 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 highway turns northwest briefly before turning north and exiting Weber County, the Ogden-Clearfield metropolitan area, and the Wasatch Front.

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, 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.