U.S. Highway 26 is an east–west United States Numbered Highway that runs from Seaside, Oregon, to Ogallala, Nebraska. When the U.S. Numbered Highway System was first defined, it was limited to Nebraska and Wyoming; by the 1950s, it continued into Idaho and Oregon. The highway's eastern terminus is in Ogallala at an intersection with Interstate 80 (I-80). Its western terminus is south of Seaside at an intersection with US 101. Prior to 2004, the route's last 20 miles (32 km) were cosigned with US 101 from the highways' junction south of Seaside north to Astoria where its intersection with US 30 was also US 30's western terminus. Long segments of the highway follow the historic Oregon Trail. At its peak, immediately before the establishment of the Interstate Highway System, US 26 was 1,557 miles (2,506 km) in length and terminated in Astoria.

Seaside is a city in Clatsop County, Oregon, United States, on the coast of the Pacific Ocean. The name Seaside is derived from Seaside House, a historic summer resort built in the 1870s by railroad magnate Ben Holladay. The city's population was 6,457 at the 2010 census.