South Valley is a census-designated place (CDP) and unincorporated town in Bernalillo County, New Mexico, United States. The population was 40,976 at the 2010 Census. It is part of the Albuquerque Metropolitan Statistical Area. The U.S. Postal Service uses "Albuquerque" for all South Valley addresses (ZIP code 87105). According to the United States Census Bureau, the CDP has a total area of 30.2 square miles (78.3 km²), of which, 29.5 square miles (76.5 km²) of it is land and 0.7 square miles (1.8 km²) of it (2.35%) is water.