There are 4 US Post Offices in Atoka County serving a total of 11,778 residents equating to 2,945 residents per post office. It's estimated that approximately 18,799 packages are handled across the 4 county post offices annually. Atoka County is a county located in the U.S. state of Oklahoma. As of the 2010 census, the population was 14,007. Its county seat is Atoka. The county was formed before statehood from Choctaw Lands, and its name honors a Choctaw Chief named Atoka."