The Brazos River is the longest river flowing entirely in Texas, with its watershed stretching from New Mexico to the Gulf of Mexico.
The Brazos River draw lies approximately 50 miles west of the Texas-New Mexico state line, beginning a watershed that stretches 1,050 miles and comprises 45,510 square miles, 42,830 of which are in Texas. Texas compromises 94% of the watershed, while only 6% is located in New Mexico.
The Brazos River proper is formed at the confluence of the upper forks of the river, the Salt and Double Mountain, in Stonewall County. The Clear Fork joins the river just above Possum Kingdom Lake in Young County. The river enters the Gulf of Mexico two miles south of the city of Freeport in Brazoria County.
The Brazos crosses most of the physiographic regions of Texas - the High Plains, Blackland Prairie, Edwards Plateau, Coastal Sand Plains, and Gulf Coast Prairies & Marshes, offering a variety of landscapes including canyons in the upper portion, rolling hills and plains in the central, and beaches near the Gulf. The river descends at a rate of three feet to one-half foot per mile flowing 820 miles down to the Gulf of Mexico.
In addition to the Salt Fork and Double Mountain Fork, there are five other principal tributaries along the Brazos River. These include the Clear Fork, Yegua Creek and the Bosque, Little and Navasota rivers.
Within these tributaries are 15 subtributaries, including the Leon River, a tributary of the Little River. The most prevalent cities in the Brazos River basin are Lubbock, Graham, Waco, Temple, Belton, Georgetown, Round Rock, Bryan-College Station, Freeport and Galveston. The major metropolitan cities of Dallas-Fort Worth, Austin and Houston lie just outside the watershed boundaries.
Like the terrain, the climate throughout the river basin ranges significantly, from temperate to subtropical. The average annual temperature varies from 59 degrees in the upper parts to 71 degrees in the coastal area. Although winters are typically mild and brief, there have been temperatures below zero recorded.
Rainfall averages from 15 inches annually in the northwest to 50 inches in the southeast region. The soil along the basin ranges from sandy loams to deep clay. Natural vegetation consists of grasses in the dry portions to hardwoods in the wet portions. Farming and ranching is possible in almost all areas in the basin. Cotton, cattle and oil have been the most prominent products.
It is almost certain that the Brazos is the river that Indians of the Caddoan linguistic group called Tokonohono, which is preserved in narratives of past expeditions. As a result of early explorers confusing the Colorado and Brazos rivers, the name Brazos was probably first used for the Colorado River. Los Brazos de Dios, the complete name of the river, translates to "the arms of God." There are several stories explaining why it was named this; each involving the river being the first source of water fit to consume found by people that were in dire need.
The first permanent settlement on the river was San Felipe de Austin at the Atascosito Crossing of the Brazos. Founded by John McFarland, one of Stephen F. Austin's "Old Three Hundred" families the town became the colonial capital of Texas.
The Brazos at Velasco was the scene of the first colonial resistance to Mexican authority. The Brazos River settlements of Columbia and Washington-on-the-Brazos served as the first two seats of government of the Republic of Texas.
Navigation of the river became a priority to many Texans in hope of expanding trade throughout the state. With river flows alternating between drought and floods, the task was difficult as best. In the early 1900's the US Army Corps of Engineers began building a series of locks that would allow navigation as far north as the City of Waco. However, a major flood destroyed the majority of work begun and the Corps chose not to rebuild.
The natural mouth of the river was located at Quintana, two miles southeast of Freeport. However, shifting Gulf sandbars created a hazard to shipping and in 1929 the US Army Corps of Engineers diverted the mouth of the river into the Gulf Intracoastal Waterway.