Los Fresnos is a city in Cameron County, Texas. The population was 8,114 at the 2020 census, up from 5,542 at the 2010 census. Los Fresnos is a potent combination of affordability and opportunity for entrepreneurs with an eye toward the future and an interest in taking advantage of an emerging market. Los Fresnos is part of the Brownsville–Harlingen–Raymondville and the Matamoros–Brownsville metropolitan areas.