List of Interstate Highways in Washington
Interstate 90 (I-90) is the longest primary Interstate Highway in Washington, which connects Seattle to Spokane and the Idaho border, measuring , while I-82, connecting the Oregon border city of Umatilla to Elensburg via Yakima, is the shortest at . The longest auxiliary Interstate Highway in Washington is I-405, a bypass of Seattle through the Eastside, at , and the shortest is I-705, a spur into downtown Tacoma, at . One route, I-605, has been proposed over the years to form another Eastside bypass, however there are no plans to construct this fifth auxiliary route.
After passage of the Federal Aid Highway Act of 1956, which formed the Interstate Highway System, the American Association of State Highway Officials had approved I-5 and I-90 across Washington on August 17, 1957. I-82 was approved on October 17, 1957, two months after I-5 and I-90, as part of a addition to the Interstate Highway System.
Lincoln Highway
The Lincoln Highway was one of the earliest transcontinental highways for automobiles across the United States of America. Conceived in 1912 by Indiana entrepreneur Carl G. Fisher, and formally dedicated October 31, 1913, the Lincoln Highway ran coast-to-coast from Times Square in New York City west to Lincoln Park in San Francisco, originally through 13 states: New York, New Jersey, Pennsylvania, Ohio, Indiana, Illinois, Iowa, Nebraska, Colorado, Wyoming, Utah, Nevada, and California. In 1915, the "Colorado Loop" was removed, and in 1928, a realignment relocated the Lincoln Highway through the northern tip of West Virginia. Thus, there are a total of 14 states, 128 counties, and more than 700 cities, towns and villages through which the highway passed at some time in its history.