Rio Rancho is the largest and most populous city in Sandoval County, New Mexico, United States. A small portion of the city extends into northern Bernalillo County. Part of the expansive Albuquerque metropolitan area, it is the third-largest city in New Mexico, and one of the most rapidly growing. Rio Rancho had a population of 104,046 at the 2020 census. The name Rio Rancho derives from Los Ranchos, the Spanish colonial ranches established along the Rio Grande in the Albuquerque Basin, and throughout historic Nuevo México. There were large ranches also in neighboring Corrales. Since the late 20th century, it has developed as a suburb of Albuquerque.