U.S. Route 99 - History

History

An extensive section of this highway (over 600 miles), from approximately Stockton, California to Vancouver, Washington, follows very closely the track of the Siskiyou Trail. The Siskiyou Trail was based on an ancient network of Native American footpaths connecting the Pacific Northwest with California's Central Valley. By the 1820s, trappers from the Hudson's Bay Company were the first non-Native Americans to use the route of U.S. Highway 99 to move between today's Washington state and California. During the second half of the 19th Century, mule train trails, stagecoach roads, and the path of the Central Pacific railroad (later the Southern Pacific railroad) also followed the route of the Siskiyou Trail. By the early 20th Century, pioneering automobile roads were built along the Siskiyou Trail, including most notably the Pacific Highway. The Pacific Highway ran from British Columbia to San Diego, California and is the immediate predecessor of much of U.S. Highway 99. The highway was continuous pavement by the middle 1930s.