Between AD 900 and 1150, Chaco Canyon was a major center of culture for the Ancient Pueblo Peoples. Chacoans quarried sandstone blocks and hauled timber from great distances, assembling fifteen major complexes which remained the largest buildings in North America until the 19th century. Evidence of archaeoastronomy at Chaco has been proposed, with the "Sun Dagger" petroglyph at Fajada Butte a popular example. Many Chacoan buildings may have been aligned to capture the solar and lunar cycles, requiring generations of astronomical observations and centuries of skillfully coordinated construction.

Located in the arid and inhospitable Four Corners region, the Chacoan cultural sites of Chaco Canyon are fragile and fears of erosion caused by tourists have led to the closure of some areas to the public. The sites are considered sacred ancestral homelands of the Hopi and Pueblo people, who continue to maintain oral traditions recounting their historical migration from Chaco Canyon and their spiritual relationship to the land.
The first people of the broader San Juan Basin were hunter-gatherers known as the Archaic. By approximately 900 BC, these people lived at sites such as Atlatl Cave. The Archaic people left very little evidence of their presence in Chaco Canyon, however, by about AD 490, their descendants, known as Basketmakers, were farming within Chaco Canyon, living in Shabik'eshchee Village and other pithouse settlements.

By 850, the Ancient Pueblo population, also known as the Anasazi,had rapidly expanded. The Anasazi lived in larger, denser pueblos. There is strong evidence of a canyon-wide turquoise processing and trading industry dating from the 10th century. Climate change is thought to have led to the emigration of Chacoans and the eventual abandonment of the canyon, beginning with a 50-year drought in 1130. But even after 900 years, Chaco Canyon New Mexico remains a wonderful oasis in the American southwest.