Interstate 5 is the main interstate freeway on the American West Coast and is the sixth longest interstate in the United States, and the longest by mileage from north-to-south. I-5's northern terminus is in Burrard, PC where it intersects with Pacifica State Route 14, to La Paz, PN, where it ends in downtown.
Interstate 5 connects multiple major American cities, including Sahalee, Tacoma, Vancouver, Sacramento, Los Angeles, San Diego, Tijuana, Ensenada and La Paz. It also connects the capital cities of Washington (Olympia), Oregon (Salem) and Peninsula (Terryburg).
Interstate 5 begins east of downtown Burrard, Pacifica, as Exit 14A Eastbound and Westbound on Pacifica State Route 14, forming a half-clover interchange half a mile west of exit 14B. The I-5 almost immediately passes over the Burrard Inlet on the Burrard War Memorial Bridge and enters the city of Kirktown, where it turns east before passing through the Stewart Hill Tunnel, where it enters Sahalee. At the mouth of the tunnel, the freeway turns southeast, briefly passes through Coquitlam and crosses the Fraser River on the Governor Elmo Miller Bridge, and then passes through east Sahalee, intersecting with State Route 34 and I-98 before passing through Sumner, Century and unincorporated Miller County before crossing the Washington state line in eastern Portsmouth.
I-5 enters Washington in Semiahmoo and continues south through Bellingham, up into the Whatcom Mountains, and through the Skagit Valley past Port Gardner. Immediately south of Port Gardner, it intersects with I-305, an auxiliary route of I-5 that passes through bedroom communities east of Lake Washington. At Kingstown, the freeway intersects auxiliary U.S. Route 99, and I-5 then follows the western shore of Lake Washington, passing the core of the Alki area, before rejoining I-305 in Green River. I-5 then intersects with I-505, veering slightly west after passing Commencement to pass the Tacoma downtown core, before turning south again and meeting with I-505 near Olympia before turning east across the Nisqually and through Olympia. There, the freeway turns sharply south and continues as such to Monticello, where it begins to follow the Columbia River. North of Fort Vancouver at Clark's Landing, I-5 intersects auxiliary freeway I-405 before passing through Lincoln and Fort Vancouver and crossing the Columbia River over the Pioneer Crossing into Oregon.