Amistad Dam, Texas

Lake Amistad is the largest body of water in West Texas, though it is not entirely in Texas, as it is shared by Mexico. The lake formed when the Rio Grand was blocked by the Amistad Dam, which was completed in 1969. The border runs through the middle of the dam. The lake, a water supply and recreational reservoir, covers a hundred square miles of what used to be the river valley. It is managed by the International Boundary and Water Commission, the bi-national entity that oversees the entire border between Mexico and the USA.