There are 7 US Post Offices in Ferry County serving a total of 6,418 residents equating to 917 residents per post office. It's estimated that approximately 10,244 packages are handled across the 7 county post offices annually. Ferry County is a county located in the U.S. state of Washington. As of the 2010 census, the population was 7,551, 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 on February 21, 1899 and is named for Elisha P. Ferry, the state's first governor."