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.
List of Interstate Highways in Nebraska
The Interstate Highways in Nebraska are the segments of the national Interstate Highway System that are owned and maintained by the U.S. state of Nebraska, totaling . The longest of these, by far, is Interstate 80 (I-80) at a length just over . After the system was created in 1956, the state department of roads began construction on its Interstates immediately and upon completion of I-80 in 1964 was the first state to complete its mainline Interstate. With the completion of Interstate 129 in 1977, Nebraska completed its contribution to the Interstate Highway System.