Construction of Pueblo Bonito, the best-known Chacoan great house, began by the mid-9th century, marking the start of a long, staged building program that helped anchor Chaco Canyon’s emerging regional importance.
During the Bonito Phase (roughly 900–1140 CE), Chacoan communities constructed and expanded numerous great houses, reflecting a major intensification of monumental architecture and associated social and ceremonial life in the canyon and its outliers.
Work began on Chetro Ketl, one of Chaco Canyon’s largest great houses by footprint. Its long construction history (beginning around 990–1000 CE) illustrates how major public architecture was built and remodeled over generations.
Initial construction at Pueblo Alto began around 1020 CE on the mesa north of the canyon. The site’s scale and location highlight Chaco’s planned monumental building beyond the main canyon-floor cluster.
Construction of Casa Rinconada’s large, stand-alone great kiva likely began in the mid-11th century and it appears to have been used into the early 12th century, indicating major communal-ceremonial activity beyond great-house plazas.
Building began at Pueblo del Arroyo in the 1060s. Unlike many great houses tucked against canyon walls, it was built more openly near the wash, and later gained a distinctive tri-wall structure.
By about 1075 CE, the main construction program at Chetro Ketl was largely complete (with later remodeling continuing into the early 1100s). This milestone reflects the height of Chacoan monumental building capacity.
Pueblo Bonito’s planned, staged construction continued for centuries—an architectural record of sustained investment in the canyon’s central community. The extended sequence is a key indicator of Chaco’s enduring role as a regional node.
Kin Kletso was constructed around 1125–1130 CE based on clustered tree-ring dates. Its McElmo-style masonry and layout reflect late Chaco-era architectural changes and likely shifting populations and affiliations in the canyon.
Tree-ring–based paleoclimate research identifies an intense drought interval in the mid-12th century (about 1135–1170 CE), a climatic stressor frequently discussed in connection with changes in settlement, building activity, and regional reorganization across the northern Southwest.
By about 1140 CE, sources commonly describe substantial movement of people away from Chaco Canyon, coinciding with drought-era disruption and broader shifts in where and how great-house traditions were maintained.
Construction at Pueblo Bonito ceased by about 1150 CE, closing the primary architectural arc of Chaco Canyon’s best-known great house and aligning with broader late-Chaco transformations in building, occupation, and regional connectivity.
Chaco Canyon Architectural and Community Development (c. 850–1150 CE)
