Sentinel Mesa is a 6,450-foot summit in Monument Valley on Navajo Nation land in southeastern Utah, about 1.5 miles north of the visitor center and just northwest of the West and East Mitten Buttes. Its name reflects its commanding view over the valley, and in Navajo tradition it is one of Monument Valley’s “door posts.” The mesa is formed from layered rock including Organ Rock Shale, De Chelly Sandstone, the Moenkopi Formation, and Shinarump Conglomerate, dating from the Permian to the Late Triassic. Monument Valley’s shape has been strongly influenced by the faster erosion of softer shale beneath harder sandstone, and the mesa drains west to Mitchell Butte Wash and east to West Gypsum Creek.