Interstate 5

Interstate 5
I-5 highlighted in red
Route information
Length	1,381.29 mi[1] (2,222.97 km)
Existed	1956–present
History	Completed in 1979
NHS	Entire route
Major junctions
South end	Fed. 1 / Fed. 1D at the Mexican border in San Diego, CA
Major intersections	SR 15 in San Diego, CA I-8 in San Diego, CA I-10 / US 101 in Los Angeles, CA US 50 in Sacramento, CA I-80 in Sacramento, CA US 20 in Albany, OR I-84 / US 30 in Portland, OR US 101 in Tumwater, WA I-90 in Seattle, WA US 2 in Everett, WA
North end	Highway 99 at the Canadian border at Blaine, WA
Location
Country	United States
States	California, Oregon, Washington
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future

Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of California, Oregon, and Washington, serving several large cities on the West Coast, including San Diego, Los Angeles, Sacramento, Portland, and Seattle. It is the only continuous Interstate highway to touch both the Mexican and Canadian borders. Upon crossing the Mexican border at its southern terminus, the highway continues to Tijuana, Baja California, as Mexican Federal Highway 1 (Fed. 1). Upon crossing the Canadian border at its northern terminus, it continues to Vancouver as British Columbia Highway 99 (BC 99).

I-5 was originally created in 1956 as part of the Interstate Highway System, but it was predated by several auto trails and highways built in the early 20th century. The Pacific Highway was built in the 1910s and 1920s by the states of California, Oregon, and Washington, and was later incorporated into U.S. Route 99 (US 99) in 1926. I-5 largely follows the route of US 99, with the exception of portions south of Los Angeles and in the Central Valley of California. The freeway was built in segments between 1956 and 1978, including expressway sections of US 99 that were built earlier to bypass various towns along the route. US 99 was removed in 1972.