From its source, it flows generally east-southeastward to join the Double Mountain Fork to form the Brazos River about 18 mi (29 km) west-northwest of Haskell, Texas.

The Salt Fork Brazos River begins as a dry channel (draw) near the edge of the Llano Estacado in Crosby County, about 1.8 mi (2.9 km) southwest of the cotton gin in the small farming community of Cap Rock, Texas.

From the edge of the Caprock Escarpment, the stream channel generally runs southeastward across southern Crosby County, passing to the east of Courthouse Mountain and crossing Texas State Highway 207.

The stream then begins tending in a more easterly direction as it meanders wildly, eventually crossing from Garza into Kent County, where it merges with the White River just before it passes beneath Farm to Market Road 1081.

The stream is directed north by the high ground that surrounds Double Mountains, a pair of flat-topped hills located 13 mi (21 km) southwest of Aspermont, Texas.