Galveston County (/ˈɡælvᵻstən/ GAL-viss-tən) is a county in the U.S. state of Texas. As of the 2010 census, the population was 291,309. Its county seat is Galveston. League City is the most populous city in Galveston County; between 2000 and 2005 it surpassed Galveston as the county's largest city. The county was founded in 1838. Galveston County is part of the Houston-The Woodlands-Sugar Land, TX Metropolitan Statistical Area.