Interstate 15 (I-15) is an interstate highway that begins near the border of the United States and Mexico in San Diego County and runs north to Alberta, Canada. The highway passes through California, Nevada, Arizona, Utah, Idaho and Montana. I-15’s southern terminus is at a junction with I-8 and State Route 15 in San Diego County; its northern terminus is in Sweet Grass, Montana, at the U.S. border with Canada (where it becomes Alberta Highway 4). From end to end, I-15 is 1,433 miles long.
Along...