Red River

1 River, 1,222 mi (1,967 km) long, southernmost of the large tributaries of the Mississippi River. It rises in two branches in the Texas Panhandle and flows SE between Texas and Oklahoma and between Texas and Arkansas to Fulton, Ark. It then turns southward, enters Louisiana, and crosses SE to the Atchafalaya and the Mississippi rivers. In Texas it flows rapidly through a canyon in semiarid plains, but later in its course it waters rich red-clay farm lands (whence the name Red). Dams on the river include the Denison Dam (completed 1943), which impounds Lake Texoma, one of the largest reservoirs in the United States. For many years navigation was difficult on the lower course of the Red River due to fallen trees that floated downstream and collected behind obstructions, forming rafts. The Great Raft, a 160-mi (257-km) log-jam built through the centuries, was cleared from the river in the mid-1800s. The river is now navigable for small ships to above Natchitoches, La. There are many lakes along the lower part of the river, and reservoirs serve as flood-control units on its tributaries.

2 River, often called the
Red River of the North,
c.310 mi (500 km) long, formed N of Lake Traverse, NE S.Dak., by the confluence of the Bois de Sioux and the Otter Tail rivers. It flows N between Minnesota and North Dakota and crosses the Canadian border into Manitoba, emptying into Lake Winnipeg. The river drains the principal spring wheat-growing area of the United States and Canada-the rich Red River valley region, the bed of the ancient Lake Agassiz. Its valley is subject to sometimes devastating spring floods, and the Red River Floodway was built in the 1960s to send floodwaters around Winnipeg. The river's chief tributary is the Assiniboine.