King County is a county located in the U.S. state of Texas. The population was 265 at the 2020 census, making it the second-least populated county in Texas and the third-least populated county in the United States. King County has no incorporated communities. Its county seat is the census-designated place (CDP) of Guthrie. The county was created in 1876 and organized in 1891. It is named for William Philip King, who died at the Battle of the Alamo.