San Antonio is the second-largest city in the state of Texas and the seventh-largest in the United States. As of the 2005 U.S. Census estimate, the city had a population of over 1.2 million. As of 2006, the eight-county metropolitan area has a population of 1.9 million and is the 29th-largest metropolitan area in the United States. San Antonio, which is the county seat of Bexar County, covers over 400 square miles on the northern edge of the South Texas region in the American Southwest.