Regionally, parts of the county are within the extreme southernmost fringe of the regions locally known as Southeast Texas. Brazoria County is among a number of counties that are part of the region known as the Texas Coastal Bend. Its county seat is Angleton, and its largest city is Pearland. Brazoria County, like nearby Brazos County, takes its name from the Brazos River. The county also includes what was once Velasco, Texas, which was the first capital of the Republic of Texas. It served as the first settlement area for Anglo-Texas, when the Old Three Hundred immigrated from the United States in 1821.
Brazoria County, like Brazos County, takes its name from the Brazos River, which flows through it. Anglo-Texas began in Brazoria County when the first of Stephen F. Austin's authorized 300 American settlers arrived at the mouth of the Brazos River in 1821. Many of the events leading to the Texas Revolution developed in Brazoria County. In 1832, Brazoria was organized as a separate municipal district by the Mexican government, and so became one of Texas original counties at independence in 1836.
Stephen F. Austin's original burial place is located at a church cemetery, Gulf Prairie Cemetery, in the town of Jones Creek, Texas, on what was his brother-in-law's "Peach Point Plantation". His remains were exhumed in 1910 and brought to be reinterred at the state capital in Austin. The town of West Columbia served as the first capital of Texas, dating back to pre-revolutionary days..
Temple Lea Houston, youngest son of Sam Houston, was c. 1880 the county attorney of Brazoria County. His life story is reflected in the 1963 film The Man from Galveston and the 26-episode 1963-1964 NBC western television series, Temple Houston.
Lake Jackson is a community developed beginning in the early 1940s to provide housing to workers at a new Dow Chemical Company plant in nearby Freeport. The county has elements of both rural and suburban communities, as it is part of the Greater Houston area.