There are 18 US Post Offices in Mclennan County serving a total of 173,027 residents equating to 9,613 residents per post office. It's estimated that approximately 276,170 packages are handled across the 18 county post offices annually. McLennan County is a county located on the Edwards Plateau in Central Texas. As of the 2010 census, its population was 234,906. Its county seat is Waco. The U.S. census 2015 county population estimate is 245,671. The county is named for Neil McLennan, an early settler. McLennan County is included in the Waco, TX Metropolitan Statistical Area."