I15

Interstate 15 (I-15) is a major north-south highway in the western United States. It begins at an interchange with I-215 on the southern edge of San Bernardino, California, and travels north through the Mojave Desert, across Nevada, through Utah, into Idaho, and into Montana, ending at the Canadian border near Sweet Grass, where it continues as Alberta Highway 2. The route covers roughly 1,433 miles (2,306 km).

I-15 serves several large urban areas and is a key freight corridor. It connects the Las Vegas metropolitan area with Salt Lake City and the broader Intermountain West, and provides a link to Boise and other communities in Idaho. The highway supports substantial long-distance trucking and regional commerce, with segments designed to accommodate heavy traffic and weather-related maintenance challenges, including desert heat, snow in the mountains, and occasional closures.

Construction and development occurred in segments as part of the original Interstate Highway System initiative. Work progressed through the 1950s onward, with completion and subsequent upgrades occurring through the late 20th century and into the present. The corridor has seen ongoing improvements to widen lanes, modernize interchanges, and enhance safety and reliability in both urban and rural sections. I-15 remains a vital backbone for transportation in the western United States.