Between 1869 and 1887, the Oregon & California Railroad Company built a railroad along this route, crossing Siskiyou Summit in 1887. In the mid-1910s, the pioneering Pacific Highway, later numbered as U.S. Highway 99, provided the first easy automobile access along the path of the trail. Interstate 5 was built in the 1960s along the route of the original 1820s Siskiyou Trail. About 4 miles (7 km) north of the California border, and just south of Ashland, Oregon, the highway crosses Siskiyou Summit, the highest point on I-5 (elevation ). The railroad and interstate highway deviate from the original trail in small ways according to the needs and engineering available to their builders.