An alluvium-filled 20-km stretch of canyon in northwest New Mexico, occupied by the Anasazi during Pueblo I and II, c 850-1150 AD. Now a national park, it contained spectacular pueblos, including Pueblo Bonito (c 919-1130) which housed some 1,200 people. There were at least a dozen pueblo-like towns and hundreds of small villages. During a period of increased rainfall between 950-1150, several other pueblos were constructed in the Canyon, with fields, irrigation canals, an elaborate road system, and signal stations for long-distance trade. The entire complex of ruins has been studied with the aid of photogrammetry, including infrared air photography, satellite photographs, image enhancement, and computer mapping. When the climate started to become dryer, in c 1150, the main occupation of Chaco Canyon ended.