WUPATKI NATIONAL MONUMENT

national monument in north-central Arizona, U.S. It lies along the Little Colorado River near the San Francisco Mountains, 30 miles (48 km) north-northeast of Flagstaff. Established in 1924, with an area of 55 square miles (142 square km), it comprises more than 800 pre-Columbian red sandstone pueblos. Studies of tree rings in their ancient wooden beams indicate that they were built between the 11th and the 13th century. Their occupants were farming Indians believed to be the ancestors of the Hopi Indians, who came with corn seed and digging sticks to cultivate the cinder soils that covered the region after the eruption (c. 1064) of nearby Sunset Crater. The outstanding groups of pueblos are the Wupatki and the Citadel, built near the rim of a sinkhole.