Frio County is named after the Spanish word for "cold", given to the county's namesake river. Martín de Alarcón crossed the area on his way to establish San Antonio de Valero Mission, as did the original Canary Islander families that went on to found the City of San Antonio. The County was finally recognized by the State of Texas in 1871.
As of the 2014 Census, Frio County had a population of 18,531, with 9,681 people living in Pearsall, the County's seat. The County is famous for its annual Potato Festival held in June.