The Aztec Ruins National Monument in northwestern New Mexico, United States, consists of preserved structures constructed by the Pueblo Indians. The national monument lies on the western bank of the Animas River in Aztec, New Mexico, about 12 miles northeast of Farmington. Additional Puebloan structures can be found in Salmon Ruins and Heritage Park, 9.5 miles south. Archaeological evidence puts the construction of the ruins in the 12th and 13th centuries.