Chaco Canyon is a historic national park located in the northwest corner of New Mexico. Along with Mesa Verde to the north, it represents one of the crown jewels of what remains architecturally of the Anasazi culture of the American Southwest. Also known as the Ancestral Puebloans, the Anasazi, and their predecessors inhabited the greater four corners region from about 7500 B.C. until 1300 A.D. The tribes of the region started out as Pleistocene big game hunters, but over time their lifestyle morphed from that of the hunter-gatherer to mostly sedentary farmers that relied on the planting of maize, squash and beans. Their development over the centuries has been defined in part by what they left behind. At first it was the implements they used to store food, from simple baskets in the beginning to elaborate clay pots in later centuries. In later eras it was their housing that changed significantly, from pit houses, to the elaborate multi-story, multi-roomed mud and stone buildings they are known for today.
Based on numerous studies, scientists speculate that Chaco might have been more of a spiritual or cultural gathering center, rather than a place of permanent habitation. The way many of its buildings seem to align with important solar events, hints at a possible astronomical significance, that would have required scientific observation of the moon, sun and stars over many generations.
Between, 1100-1300 A.D. the Anasazi began to abandon much of region they inhabited, with Chaco seeing the last inhabitants about 1150. Many theories have been presented regarding their migration away from the region, but one thing is fairly clear, that the climate had become unreliable in later years, making their settled agricultural lifestyle harder and harder to maintain. In Chaco, evidence of a 50 year drought occurring during the period it was finally abandoned, is one of many example. Increasing strife and warfare is another possibility they faced.
While the Anasazi may have moved away, they did not really disappear. Their ancestors include the Hopi of Arizona and the Zuni of New Mexico.
Suggested Reading:
Archeoastronomy of the Chacoan Pueblo (PDF)
House of Rain: Tracking a Vanished Civilization Across the American Southwest – Craig Childs
The Lost World of the Old Ones: Discoveries in the Ancient Southwest – David Roberts
Non-Technical Canyon Hiking Guide to the Colorado Plateau – Mike Kelsey
Grand Gulch, Cedar Mesa Plateau Maps – National Geographic Trails Illustrated Maps