McKinney Falls State Park is a state park in Austin, Texas, United States at the confluence of Onion Creek and Williamson Creek. It is administered by the Texas Parks and Wildlife Department. The park opened on April 15, 1976 and is named after Thomas F. McKinney, a businessman, race horse breeder and rancher, who owned and lived on the land in the mid-to-late 19th century. The park is part of the El Camino Real de los Tejas National Historic Trail.