Bexar County (/bɛər/ BAIR, /ˈbeɪ. ər/ BAY-ər) is a county of the U. S. state of Texas. As of the 2010 census, the population was 1,714,773, and a 2018 estimate put the population at 1,986,049. It is the 16th-most populous county in the nation and the fourth-most populated in Texas. Its county seat is San Antonio, the second-most populous city in Texas and the seventh-largest city in the United States.