There are 5 US Post Offices in Douglas County serving a total of 8,551 residents equating to 1,710 residents per post office. It's estimated that approximately 13,648 packages are handled across the 5 county post offices annually. Douglas County is a county located in the U.S. state of Washington. As of the 2010 census, its population was 38,431. The county seat is Waterville, while its largest settlement is East Wenatchee Bench, although East Wenatchee is the commercial center. The county was created out of Lincoln County on November 28, 1883 and is named for American statesman Stephen A. Douglas. Douglas County is part of the Wenatchee, WA Metropolitan Statistical Area."