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.

Port Lavaca is a city in Calhoun County, located in the U.S. state of Texas. The population was 12,248 at the 2010 census and 11,557 at the 2020 census. It is the county seat of Calhoun County and part of the Port Lavaca, Texas micropolitan statistical area. Port Lavaca is 130 miles (210 km) southwest of Houston.