Southlake is a city in northeastern Tarrant and southern Denton Counties in the U.S. state of Texas. It is a suburb of Fort Worth and is located near the cities of Grapevine, Colleyville, and Keller. The Southlake area was settled by pioneers in the 1840s, but was not incorporated Southlake until 1956, four years after Lake Grapevine was finished. The population was 21,519 at the 2000 census. In December 2008, Forbes. com named Southlake the most affluent neighborhood in the United States based on average median household income estimates. Southlake is well known for its Southlake Town Square project, a shopping center located on State Highway 114 and Southlake Boulevard. A plan was approved in March 2005 that allowed the Town Square's area to be doubled. Southlake is well known for the Southlake Carroll Dragons. Sabre Holdings, an S&P 500 company and owner of Travelocity, is headquartered in Southlake. Industrial businesses include gasoline storage and distribution and concrete works.