Ferry County is a county located on the northern border of the U.S. state of Washington. As of the 2020 census, the population was 7,178, making it the fourth-least populous county in Washington. The county seat and largest city is Republic. The county was created out of Stevens County in February 1899 and is named for Elisha P. Ferry, the state's first governor.

Republic is a city in Ferry County, Washington, United States. The population was 992 at the 2020 census. It is the county seat of Ferry County. It was the largest mining camp in the Republic Mining District, and home to the "Hot Air Line" railway.