I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Canada. The Interstate serves the cities of San Diego, San Bernardino, Las Vegas, St. George, Provo, Salt Lake City, Ogden, Pocatello, Idaho Falls, Butte, Helena, and Great Falls. It also passes close to the urban areas of Los Angeles, Orange, and Riverside counties, California. Since its creation, I-15 has served as a long-haul route for North American commerce.