Pasco (/ˈpæskoʊ/ PAS-koh) is a city in, and the county seat of, Franklin County, Washington, United States. The population was 77,108 at the 2020 census, and 79,315 as of the July 1, 2022 estimate.
On October 16, 1805, the Lewis and Clark Expedition camped in the Pasco area, at a site now commemorated by Sacajawea State Park.