Caddo Lake is a 25,400 acres lake and wetland located 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 Southeastern culture of Native Americans called Caddoans or Caddo, who lived in the area until their expulsion in the 19th century. It is an internationally protected wetland under the RAMSAR treaty and features the largest Cypress forest in the world. Caddo is one of Texas' few non-oxbow natural lakes and is the 2nd largest in the South; however, it was artificially altered by the addition of a dam in the 1900s.Caddo Lake has been utilized by Native Americans for thousands of years, but substantial commercial development would only begin with invention of the steamboat and US annexation of Louisiana and Texas by treaty in the 19th century. The cities of Port Caddo, Swanson's Landing, and Jefferson in Texas, and Mooringsport in Louisiana, had thriving riverboat ports on the lake. Gradually as the log jams were removed in the lake and the Red River by Captain Henry Miller Shreve and then by the Army Corps of Engineers, the lake changed shape and eventually fell over ten feet, destroying the East Texas ports and their riverboat industry.Industry once again came to Caddo Lake with the discovery of oil beneath it. The world's first over water oil platform was completed in Caddo Lake in 1911. The Ferry Lake No. 1 was erected by Gulf Refining Company. The well bottomed at 2,185 feet and produced 450 barrels per day.Oil derricks sprang up throughout the lake, around the turn of the 20th century, further damaging the fragile ecosystem. The oil industry left Caddo for richer fields at Kilgore and other locations in Texas. Texas tried to preserve parts of Caddo in 1934 by establishing a State Park, constructed by the WPA. The establishment of the Longhorn Army Ammunition Plant on the shores of Caddo, in the mid 20th century, polluted large portions of the surrounding wetlands until its closure in the 1990s.An ecologist named Lionel Janes conducted a survey of Caddo Lake in 1913 and 1914. Based on an examination of cross sections of baldcypress and hardwood trees and many dead stumps he estimated that the lake came into existence sometime between 1770 and 1780.