History
Brazos County: from Stephen F. Austin's colony to county seat at Bryan
Brazos County was created in 1841, originally named Navasota County, and moved its county seat from Boonville to Bryan in 1866 to follow the railroad.
The land that became Brazos County was part of Stephen F. Austin's second colony, granted under Mexican rule in the 1820s. The Republic of Texas Congress created Navasota County in 1841 and changed the name to Brazos County in 1842. The county sits between the Navasota and Brazos rivers and covers about 588 square miles in southeast central Texas.
Boonville was the first county seat. When the Houston and Texas Central Railroad arrived in the mid-1860s, county residents voted 190 to 42 to move the county seat to Bryan. Bryan was a village on land once owned by William Joel Bryan, a nephew of Stephen F. Austin. The railroad reached Bryan in 1867.
Cotton dominated farming through the early 1900s. German, Austrian, Czech, and Italian immigrants arrived in large numbers starting in the 1870s. Oil was discovered in 1942. The TSHA Handbook of Texas and the Texas Almanac both document the county's full history.
Source to confirm: TSHA – Brazos County