Chaco Canyon

Chaco is two things at once: an archaeological problem of the first rank, and a live political fight over the ground it stands on.

What the Chacoans built. Between about 850 and 1150 a society centred on this dry canyon raised great houses of coursed sandstone, some rising to five storeys and holding hundreds of rooms, and laid out wide, straight roads running for tens of kilometres to outlying "great house" communities across the San Juan basin. Several buildings encode astronomy: walls and windows aligned to the solstices, and to the 18.6-year cycle of the moon's standstills. This was a planned centre coordinating a region, not a single town.

What became of them. In the twelfth century the system contracted and the population moved north and then south, to the mesas and river valleys where the Pueblo nations live today. Chaco is ancestral to them in a direct and stated sense; it is not a ruin of strangers.

The fight now. In June 2023 the Department of the Interior withdrew federal land within roughly ten miles of the park from new oil and gas leasing for twenty years, a protection Pueblo nations had sought for decades. The Navajo Nation objected, because Navajo allottees hold land inside the buffer and draw royalty income from it, a genuine split between tribal governments, not a simple story of natives versus industry. In 2026 the Bureau of Land Management moved to rescind the withdrawal on a two-week comment window, and Pueblo leaders opposed both the substance and the haste. The atlas records the positions and the parties, and does not decide between them.

Chaco's largest great house held goods traded from thousands of kilometres away, and the modern landscape around the canyon is now the subject of an active fight over oil and gas leases.

A great house built for more than local use

Pueblo Bonito, the largest of Chaco Canyon's great houses, was built in multiple construction phases reaching several stories and hundreds of rooms, and excavations recovered turquoise, copper bells and the remains of scarlet macaws, birds native to Mexico and Central America, evidence of long-distance trade and exchange networks reaching far beyond the immediate region.

A modern fight over the land nearby

Land surrounding Chaco Canyon has been subject to extensive oil and gas leasing, and Indigenous-led advocacy, including from Navajo and Pueblo communities with ancestral ties to the site, has pushed for a protective buffer zone limiting drilling near the canyon, a live contemporary land-use dispute that sits alongside, but is distinct from, the scholarly debate over the ancient road and alignment system.

As this entry's companion article covers

Chaco's extensive network of engineered roads radiating outward from the canyon, and the specific astronomical alignments built into several great houses, along with the still-unresolved scholarly dispute over their exact purpose, are addressed directly in this entry's companion article rather than repeated here.