Cameron County is the southernmost county in the U.S. state of Texas. As of the 2010 census, its population was 406,220. Its county seat is Brownsville. The county was founded in 1848 and is named for Captain Ewen Cameron, a soldier during the Texas Revolution and in the ill-fated Mier Expedition.
Cameron County is part of the Brownsville–Harlingen, TX Metropolitan Statistical Area as well as the Brownsville–Harlingen–Raymondville, TX Combined Statistical Area.
According to the U.S. Census Bureau, the county has a total area of 1,276 square miles (3,300 km2), of which 891 square miles (2,310 km2) is land and 386 square miles (1,000 km2) (30%) is water. To the east, the county borders the Gulf of Mexico.