San Antonio is a city in the U.S. state of Texas and the most populous city in Greater San Antonio, the third-largest metropolitan area in Texas and the 24th-largest metropolitan area in the United States at 2.6 million people in the 2020 U.S. census. It is the most populous city in and the county seat of Bexar County. San Antonio is the seventh-most populous city in the United States, and the second-most populous in the Southern United States and Texas, after Houston.