Leon Valley is a city in Bexar County, Texas, United States. It is an enclave of San Antonio and is part of the San Antonio-New Braunfels Metropolitan Statistical Area. The population was 9,239 at the 2000 census; the July 1, 2009 Census estimate, however, showed the population had grown to 11,020. Leon Valley is an independent municipality completely surrounded by the city of San Antonio. According to the United States Census Bureau, the city has a total area of 3.4square miles (8.8Square kilometers), all of it land. Leon Valley was developed in the 1950s. In 1952 residents filed a petition for incorporation as a city since the residents did not wish to be annexed by San Antonio. Leon Valley had a population of 536 in 1960. Sometime in the 1960s Leon Valley incorporated as a city. Its population grew to 1,960 in 1970. In 1990 it had 9,581 people.