Freeport is a city in Brazoria County, Texas, United States, located on the Gulf of Mexico. According to the 2020 census, the city population wa…Freeport is a city in Brazoria County, Texas, United States, located on the Gulf of Mexico. According to the 2020 census, the city population was 10,696, down from 12,049 in 2010. Freeport was founded as a European-American settlement in November 1912 by the Freeport Sulphur Company. The population was 300. However, by 1929, that population had grown to 3,500, and to 4,100 by 1939, influencing a steady increase of economic expansion in Freeport.