Calhoun County is a county located in the U.S. state of Texas. As of the 2020 census, the population was 20,106. Its county seat is Port Lavaca. The county is named for John Caldwell Calhoun, the seventh vice president of the United States. Calhoun County comprises the Port Lavaca, TX Micropolitan Statistical Area, which is also included in the Victoria-Port Lavaca, TX Combined Statistical Area.