There are 2 US Post Offices in Douglas County serving a total of 9,922 residents equating to 4,961 residents per post office. It's estimated that approximately 15,837 packages are handled across the 2 county post offices annually. Douglas County is a county located in the south-central portion of the U.S. state of Missouri. As of the 2010 census, the population was 13,684. The county seat and only incorporated community is Ava. The county was officially organized on October 19, 1857, and is named after U.S. Senator Stephen A. Douglas (D-Illinois) and later Democratic presidential candidate."