Mule Canyon Ruin is an open Anasazi habitation site with both above- and below-ground structures, first occupied briefly in the Pueblo I period about A.D. 750 and mainly occupied during the Pueblo II and Pueblo III transition about A.D. 1000 to 1150. Its visible features include an L-shaped block of 12 rooms, a masonry kiva, and a tower connected by two crawlways, along with a subterranean pithouse, a dirt-walled kiva, and trash areas. Two or three family groups used the room block primarily for sleeping and storage, entering through roof hatchways with ladders as well as doorways, while cooking and other daily activities took place on the roof or in the plaza during good weather. The underground kiva served as a focal point for ceremonial activities that archaeologists, drawing on studies of contemporary Pueblo Indians descended from the Anasazi, believe were reserved primarily for males; it was roofed with logs, usually juniper, covered with earth, and entered through a roof opening by ladder as well as by uncommon tunnels. The circular tower was probably two stories high, and although its function is unknown, it may have been used for solar observation, defense, communication, storage, or ceremonial practices. Because Mule Canyon Ruin is in direct line of sight with Cave Towers one mile to the southeast, the towers may have been used for signaling between the two communities. Botanical studies show that corn, beans, and squash were staple foods, supplemented by a variety of wild plant and animal foods. Pottery and architecture indicate a strong influence from the Mesa Verde subculture of the Anasazi from southwest Colorado, while numerous pottery fragments and the square kiva at Butler Wash Ruin six miles to the east also show Kayenta influence from northwest Arizona. Archaeologists from the University of Utah excavated the site in 1973, with special attention to the structures and trash areas, and the ruin was stabilized by the National Park Service in 1973 and 1974.