There are 3 US Post Offices in Zapata County serving a total of 13,798 residents equating to 4,599 residents per post office. It's estimated that approximately 22,023 packages are handled across the 3 county post offices annually. Zapata County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 14,018. Its county seat is Zapata. The county is named for Colonel Jose Antonio de Zapata, a rancher in the area who rebelled against Mexico. Zapata County comprises the Zapata, TX Micropolitan Statistical Area. The South Texas Oil Boom included wells drilled in Zapata County in the early 1920s through the work of Laredo industrialist Oliver Winfield Killam, a Missouri native who once served as an Oklahoma state legislator. It is east from the Mexico\u2013United States border."