The Brazos is the longest river in Texas and the 11th longest river in the United States at 2060 km (1280 miles) from its source at the head of Blackwater Draw, Curry County, New Mexico to its mouth at the Gulf of Mexico with a 116,000 km² (44,800 sq mi) drainage basin.
The Brazos proper begins at the confluence of its Salt Fork and Double Mountain Fork (two tributaries of which rise west of Lubbock and pass through that city) flowing 840 miles through the middle of Texas. Its main tributaries are the Clear Fork Brazos River, which passes by Abilene and joins the main river near Graham; Bosque River; Little River; Yegua Creek; and Navasota River. Initially running east towards Dallas-Fort Worth, the Brazos turns south, passing through Waco, further south to near Calvert, Texas then past Bryan and College Station, then through Richmond, Texas in Fort Bend County, and into the Gulf of Mexico in the marshes just south of Freeport.
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, and its proposed construction in the mid-1950s became the impetus for John Graves' book, Goodbye to a River. There is also a small municipal dam (Lake Brazos Dam) near the downstream city limit of Waco, which raises the level of the river through the city to form a town lake. This impoundment of the Brazos through Waco is locally called Lake Brazos. There are nineteen major reservoirs along the Brazos.