Homes Near Florence Elementary in Southlake, TX Why Do People Live here? Southlake is an affluent suburban city located in Tarrant and Denton Counties within the state of Texas.The city of Southlake is located within the Dallas-Fort Worth metropolitan area. As of the 2010 census it had a population of 26,575. Southlake is known for exemplary public schools, Southlake Town Square, its wealth, and Carroll High School's 8-time state champion football team. In December 2008, Forbes.com named Southlake the most affluent neighborhood in the United States based on average median household income estimates. The mean household income for the city (0 comments)