Canyon Lake is a census-designated place (CDP) in Comal County, Texas, United States. The population was 21,262 at the 2010 census. It is part of the San Antonio Metropolitan Statistical Area. The Canyon Lake CDP includes a number of small, unincorporated communities surrounding Canyon Lake, including Sattler, Startzville, Canyon City, Cranes Mill, and Hancock. Communities located on the fringes of the CDP are Fischer, Spring Branch, and Smithson Valley.