There are 31 US Post Offices in Oklahoma County serving a total of 507,338 residents equating to 16,366 residents per post office. It's estimated that approximately 809,768 packages are handled across the 31 county post offices annually. Oklahoma County is a county located in the central part of the U.S. state of Oklahoma. As of the 2010 census, the population was 718,633, making it the most populous county in Oklahoma. The county seat is Oklahoma City, the state capital. Oklahoma County is at the heart of the Oklahoma City Metropolitan Statistical Area. Oklahoma County is one of seven counties in the United States to share the same name as the state it is located in (the other six counties are Arkansas County, Hawaii County, Idaho County, Iowa County, New York County, and Utah County).