Much of the river's length in Louisiana was unnavigable in the early 19th century because of a collection of fallen trees that formed a "Great Raft" over 160 miles (260 km) long. Captain Henry Miller Shreve cleared the logjam in 1839. The river was thereafter navigable only for small craft north of Natchitoches.
Because of a cartographic error, the land between the north and south forks was claimed by both the state of Texas and the federal government. Originally called Greer County, Texas, the U.S. Supreme Court ruled that it belonged to the federal government, which at the time oversaw the Oklahoma Territory. That territory was later incorporated into the state of Oklahoma, whose southern border now follows the south fork.
That southern fork, which is about 120 miles (190 km), is generally called the Prairie Dog Town Fork. It is formed in Randall County, Texas near the county seat of Canyon, by the confluence of intermittent Palo Duro Creek and Tierra Blanca Creek. (The names mean "Hard Wood" and "White Land", respectively, in Spanish.) It flows east-southeast, through Palo Duro Canyon in Palo Duro Canyon State Park, then past Newlin, Texas, to meet the Oklahoma state line. From there eastward, it is usually referred to as the Red River, even before meeting the north fork.
