There are 8 US Post Offices in Dewey County serving a total of 5,287 residents equating to 661 residents per post office. It's estimated that approximately 8,439 packages are handled across the 8 county post offices annually. Dewey County is a county in the western part of the U.S. state of Oklahoma. As of the 2010 census, the population was 4,810. Its county seat is Taloga. The county was created in 1891 as \"County D\". In an 1898 election, county voters chose the name Dewey, honoring Admiral George Dewey.