Clayton is a town in northern Concordia Parish, Louisiana, United States. The population was 711 at the 2010 census. Cotton is a principal commodity in the area. Clayton is located on the Tensas River, important for fishing and boating, promoted through a U.S. Army Corps of Engineers-maintained boat launch. The Tensas River merges with the Black Riv…Clayton is a town in northern Concordia Parish, Louisiana, United States. The population was 711 at the 2010 census. Cotton is a principal commodity in the area. Clayton is located on the Tensas River, important for fishing and boating, promoted through a U.S. Army Corps of Engineers-maintained boat launch. The Tensas River merges with the Black River in Jonesville in Catahoula Parish.