The Brazos River (ˈbræzəs , ˈbɾasos), called the Río de los Brazos de Dios (translated as "The River of the Arms of God") by early Spanish explorers, is the 14th-longest river in the United States at from its headwater source at the head of Blackwater Draw, Roosevelt County, New Mexico to its mouth at the Gulf of Mexico with a drainage basin. Being one of Texas' largest rivers, it is sometimes used to mark the boundary between East Texas and West Texas.
The river is closely associated with Texas history, particularly the Austin settlement and Texas Revolution eras. Today major Texas institutions such as Texas Tech University, Baylor University, and Texas A&M University are located close to the river's basin, as are parts of metropolitan Houston.
The Brazos proper begins at the confluence of the Salt Fork and Double Mountain Fork, two tributaries of the Upper Brazos that rise on the high plains of the Llano Estacado, flowing southeast through the center of Texas. Another major tributary of the Upper Brazos is the Clear Fork Brazos River, which passes by Abilene and joins the main river near Graham. Important tributaries of the Lower Brazos include the Paluxy River, the Bosque River, the Little River, Yegua Creek, the Nolan River, the Leon River, the San Gabriel River, the Lampasas River, and the Navasota River.
Initially running east towards Dallas-Fort Worth, the Brazos turns south, passing through Waco and the Baylor University campus, further south to near Calvert, Texas, then past Bryan and College Station, then through Richmond, Texas, in Fort Bend County, and empties into the Gulf of Mexico in the marshes just south of Freeport.
The main stem of the Brazos is dammed in three places, all north of Waco, forming Possum Kingdom Lake, Lake Granbury, and Lake Whitney. Of these three, Granbury was the last to be completed, in 1969. When its construction was proposed in the mid-1950s, John Graves wrote the book Goodbye to a River. The Whitney Dam, located on the upper Brazos, provides hydroelectric power, flood control, and irrigation to enable efficient cotton growth in the river valley.