Pasco 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.

Franklin County is a county located in the U.S. state of Washington. As of the 2020 census, its population was 96,749. The county seat and most populous city is Pasco. The county was formed out of Whitman County on November 28, 1883, and is named for Benjamin Franklin.