Interstate 15 in Utah partially coincident with Interstate 84 in Utah
Route description
The Interstate passes through the fast-growing Dixie region, which includes St. George and 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, I-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 I-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.Just prior to the next interchange, I-15 enters Weber County and the city of Roy. After curving slightly to the east, the freeway reaches the 5600 South (SR-97) interchange, which provides access to the north end of the airforce base, including the Hill Aerospace Museum that is located immediately north of the base. The next interchange is with Riverdale Road (SR-26). As a partial interchange, there is only a northbound offramp to eastbound SR-26 and a southbound onramp from westbound SR-26. (Eastbound SR-26 provides the only access to eastbound I-84.) At this interchange, the Interstate also transitions from Roy to Riverdale. Heading northwest, I-15 then merges with I-84, but there is no northbound access to I-84 nor westbound access from I-84 to I-15. This also begins the I-15/I-84 overlap. Immediately northwest of this interchange is the Ogden-Hinckley Airport; however, since the airport is slightly above hill, it is not visible from the freeway. Two additional lanes are added north of this junction for a total of four in each direction. Just after leaving Riverdale, the Interstate enters Ogden and reaches the 31st Street (3100 South / SR-79) interchange. Curving back to the northwest, the freeway comes to the 24th South (SR-53) interchange. Although the signage specifies "24th Street", this partial interchange (which only provides a northbound offramp and a southbound onramp) is actually with Pennsylvania Avenue (also SR-53), which promptly connects with 24th Street (2400 South) northeast of the interchange.
As it leaves Ogden and enters West Haven, I-15 curves to the north-northwest before coming to the 21st Street (2100 South / SR-104) interchange. The freeway then leaves West Haven and enters Marriott-Slaterville and immediately crosses the Weber River. The next interchange is with 12th Street (1200 South / SR-39), at which point the freeway loses one lane in each direction. Continuing on with three lanes in each direction, the Interstate reaches the 400 North interchange. Similar to the 24th Street interchange, although signage indicates "400 North", this interchanges actually connects with Pioneer Road, which promptly connects with 400 North just east of the interchange. North of this interchange, I-15 heads directly north to leave Marriott-Slaterville and enter Farr West. Continuing north, it reaches the 2700 North (SR-134) before it curves to the north-northwest and leaves Farr West and Weber County. At the 2700 North interchange, the freeway narrows to two lanes in each direction and remains so for the remainder of its route in Utah.
partially overlapping with partially intersecting with partially sharing with partially matching with partially aligning with