San Diego–Tijuana is at the junction of major interstates, state routes and federal highways. The region is at the terminus of ten major Interstates and Federal Highways. Radiating to the east and south are connections to the Imperial Valley, Mexicali Valley, and the Arizona Sun Corridor via Interstate 8, the Inland Empire, the Las Vegas Strip and metropolitan area and Salt Lake City via Interstate 15; and to the Greater Ensenada area via Federal Highway 1D. To the north and west the area is connected to the Los Angeles metropolitan area, Northern California, and Cascadia via Interstate 5. Interstate 5 and Federal Highway 1 are critical highways for commercial and international trade due to their junction at the San Ysidro Port of Entry, linking major industrial regions along the British Columbia Coast, West Coast of the United States, and the Gold Coast of Baja California at the busiest port of entry in the world. The metropolitan area is linked by Federal Highway 2 and State Route 111 to Gulf of Mexico cities.