Caddo Lake is a 25,400-acre lake and bayou on the border between Texas and Louisiana, in northern Harrison County and southern Marion County in Texas and western Caddo Parish in Louisiana. The lake is named after the Caddoans or Caddo, Native Americans who lived in the area until their expulsion by the United States in the 19th century. Th…Caddo Lake is a 25,400-acre lake and bayou on the border between Texas and Louisiana, in northern Harrison County and southern Marion County in Texas and western Caddo Parish in Louisiana. The lake is named after the Caddoans or Caddo, Native Americans who lived in the area until their expulsion by the United States in the 19th century. The US forced most of them to move west to Indian Territory.