There are 3 US Post Offices in Lampasas County serving a total of 21,049 residents equating to 7,016 residents per post office. It's estimated that approximately 33,597 packages are handled across the 3 county post offices annually. Lampasas County is a county located on the Edwards Plateau in the U.S. state of Texas. As of the 2010 census, its population was 19,677. Its county seat is Lampasas. The county is named for the Lampasas River. Lampasas County is part of the Killeen\u2013Temple, TX Metropolitan Statistical Area.