Brownsville is a city in the U.S. state of Texas and the largest city and county seat of Cameron County, located on the western Gulf Coast in South Texas, adjacent to the border with Matamoros, Tamaulipas, Mexico. The city covers 145.2 sq mi (376.066 km2), and had a population of 186,738 at the 2020 census. As of the 2020 U.S. census, it is the 136th-most populous city in the United States and 18th-most populous in Texas. It is part of the Matamoros–Brownsville metropolitan area. The city is known for its year-round subtropical climate, deep-water seaport, and Hispanic culture.