U.S. Route 91

U.S. Route 91 (US 91) is a north–south United States highway. The highway currently serves as a connection between the Cache Valley area of Utah and Idaho to the Salt Lake City and Idaho Falls population centers. Prior the mid-1970s, US 91 was an international commerce route from Long Beach, California to the Canadian border north of Sweetgrass, Montana. US 91 was routed on the main street of most of the communities it served, including Las Vegas Boulevard in Las Vegas and State Street in Salt Lake City. From Los Angeles to Salt Lake, the route was built along the corridor of the Arrowhead Trail. US 91 has been largely replaced by Interstate 15. A portion of the highway's former route in California is currently State Route 91.

Route description

Utah

US-91 begins at Brigham City and winds its way through the Wellsville Mountains using Box Elder and Wellsville Canyons for its path to the Cache Valley. Along the way it passes Mantua and Lake Mantua and passes over Sardine Summit. Once entering Cache Valley it serves as the major thoroughfare of the valley. Logan is the largest city in the valley. Both the Utah and Idaho portions of Cache Valley are part of the Logan Utah Metropolitan Statistical Area.

Interstate 15 in Nevada

Interstate 15 (I-15) is an Interstate Highway in the U.S. state of Nevada that begins in Primm, continues through Las Vegas and it crosses the border with Arizona in Mesquite. The freeway runs entirely in Clark County. Many motorists use I-15 to visit Las Vegas, as it is the only primary Interstate Highway in the city. The highway was built along the corridor of the older U.S. Route 91 (US 91) and Arrowhead Trail, eventually replacing both of these designations.

Route description

Motorists in California leave the mountainous Mojave Desert and begin a long descent through Ivanpah Valley and Ivanpah Dry Lake. I-15 crosses the Nevada state line at the first exit, Primm. Once I-15 leaves Primm, the route travels north through the desert with few services. The highway then enters the Las Vegas urban area upon passing the State Route 146 (SR 146, Saint Rose Parkway) interchange. Quickly thereafter, the Interstate meets I-215 at the Southern Beltway Interchange, which provides access to Henderson and McCarran International Airport. Originally, this interchange was termed Son of Spaghetti Bowl by the Las Vegas Review-Journal when the interchange was built.

California State Route 91

State Route 91 (SR 91) is a major east–west freeway located entirely within Southern California and serving several regions of the Greater Los Angeles metropolitan area. Specifically, it currently runs from Vermont Avenue in Gardena, just west of the junction with the Harbor Freeway (Interstate 110), east to Riverside at the junction with the Pomona (State Route 60 west of SR 91), and Moreno Valley (SR 60 and I-215 east of SR 91) freeways. The route is part of the California Freeway and Expressway System. SR 91 is part of the State Scenic Highway System from SR 55 to the east city limit of Anaheim, in the western part of the Santa Ana Canyon, and is eligible for the system through the canyon to Interstate 15.

SR 91 inherited its route number from the mostly decommissioned US 91, which passed through the Inland Empire in a northeasterly direction on its way to Las Vegas, Salt Lake City, and points beyond. Those segments of US 91 are now parallel to, or have been replaced altogether by, I-15. SR 91 officially used to head west all the way to the Pacific Coast Highway (State Route 1) in Hermosa Beach, but this segment was relinquished to local governments in 2003, and is no longer part of a state highway.