There are 18 US Post Offices in Brazoria County serving a total of 328,719 residents equating to 18,262 residents per post office. It's estimated that approximately 524,672 packages are handled across the 18 county post offices annually. Brazoria County is a county in the U.S. state of Texas. As of the 2010 census, the population of the county was 313,166. The county seat is Angleton. Brazoria County is included in the Houston-The Woodlands-Sugar Land, TX Metropolitan Statistical Area. It is located in the Gulf Coast region of Texas. Brazoria County has more species of birds than any other area in North America. 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."