Rock architects in the 9th–13th centuries: Chaco Canyon National Historic Park and World Heritage Site

There is evidence that people have been inhabiting the region we now call northern New Mexico for at least 10,000 years. But starting in the mid-800s, the Native Chaco people began to build massive, multi-story stone buildings—referred to as “great houses”—that they continued to expand for more than 300 years. In early June, we visited the Chaco Canyon historic park to learn more about these enigmatic people and their culture.

The park is located about 3.5 hours northwest of Santa Fe. The entrance road is gravel and the last part is quite rough, but we had no problems in the dry season. We stayed in the small town of Cuba, and went to the park on a day trip. I would recommend camping, if possible, to take advantage of the many trails and the views at sunrise and sunset. It was already hot in early June, so spring and fall are the best seasons for a visit. The entrance sign is a good introduction to the buildings whose remains populate the site. Many buildings have not yet been excavated.

Geology of the site

The Chaco people were expert rock masons who used the local rock, along with their adobe mortar, to construct buildings up to four stories high. What was the rock they were using?

For protection, the buildings are nestled in a wide canyon next to this rock cliff that extends northwestward from the Visitor Center where these trucks are parked. For their building materials, the masons used these rocks that were deposited during the Cretaceous Period, toward the end of the Mesozoic Era. The thin-bedded unit in the bottom part of the cliff is the Menefee Formation that was deposited ~80 million years ago at the edge of a coastal floodplain. The massive rock at the top of the cliff is the Cliff House Sandstone Formation that was deposited a few million years later.
By Cliff House time, sea level had risen and the area was at the western edge of a shallow sea, as shown by this map in the Chaco Canyon Visitor Center. Imagine an area of wide sandy beaches, quite different than the landscape today! See my June 15 post for maps of changing sea level and continents during the Mesozoic Era (

The Chaco Canyon buildings

The buildings reflect changing architectural styles during the time of their construction, starting in the 800s and continuing into the 1200s. Like archaeological sites in Mexico, many of the buildings were oriented in cardinal directions and to capture equinoxes and other solar and lunar cycles. Indeed, artifacts and petroglyphs indicate trade with people as far away as present-day Mexico. Ancient roads extending in all directions from Chaco indicate that it was probably a trading and religious center for the region.

This Kin Kletso “great house” shows how the structures were built right up to the cliff along the northeast side of the canyon. The type of stonework tells us this house was built during a later stage of the construction period. Earlier stone masons preferred the darker-colored, thinner-bedded tabular rocks, as shown in the Chaco Canyon sign at the top of the post. Later masons preferred the lighter-colored, softer rock that they fashioned into large, loaf-shaped stones, as shown in the walls of this building.
The “pièce de résistance” of Chaco Canyon is Pueblo Bonito, meaning beautiful town in Spanish. This view is southwestward across the canyon from the Pueblo Alto (high town) trail that runs along the top of the northeastern cliff. The Pueblo Bonito “great house” was the center of the Chacoan world that for more than 300 years united diverse peoples in the region. It is thought that about 1000 people lived here, but many more probably traveled here for ceremonies, commerce and trading. The central area of Pueblo Bonito would have been open, whereas the surrounding walls would have enclosed rooms stacked up to four stories high. That these walls still survive 1000 years after the area was abandoned is testimony to the Chacoan’s masonry skills.

The Pueblo Indians that still live in the region return to Chaco to pray and honor the spirits of their ancestors—the Ancestral Puebloans. Oral traditions passed down through the generations speak of clan migrations from Chaco and affirm their ties to this special area. Pueblo Indians today—for example, the Hopi, Zuni, and Navajo—are diverse groups with different cultures and languages. This reflects their origins in the different areas around the Chaco “center place” that they believe bound regional peoples through shared visions of the world. Kivas, such as the large round structures visible in the photo, are still used as a gathering place when Pueblo communities reunite to perform rituals and ceremonies. Why the Ancestral Puebloans abandoned the Chaco Canyon site and migrated to surrounding areas is still a subject of speculation.
Building against the cliff face has its risks. In 1941, after heavy rains, a large rockfall collapsed and destroyed 30 rooms that had been excavated in the 1920s. This view is northwestward. In the overview photo above, you may be able to see the large rock blocks on the south side of Pueblo Bonito (left side of photo). The large block was prophetically referred to as “Threatening Rock”, because it was a detached segment of the cliff wall, separated by a wide crack. After falling, the block’s weight was estimated as 30 tons!
Along the cliff face south of Pueblo Bonito is a series of petroglyphs. Although their meaning remains uncertain, they were probably intended as visual communications, recording important events and helping to recall stories, songs and ceremonies.

A note about historical accuracy

I had often heard references to the Anasazi people who built stone buildings in southwestern U.S. locations such as Chaco Canyon in northwestern New Mexico and Mesa Verde (now a national park) in southwestern Colorado. The word “anasazi” was interpreted as “ancient ones”. I had also heard that the Anasazi people mysteriously disappeared from the region about 1000 years ago.

This commonly-held “knowledge” is wrong on several accounts. (1) Anasazi is actually a Navajo word meaning “ancient enemy”. It is therefore a disrespectful term for a group of people that are the ancestors of native people still living in the region. (2) The people did not disappear. Their descendants still live in the area. They continue many of the traditions of their ancestors and are highly respectful of them. It is true that Europeans’ arrival was devastating to the native peoples who were tragically killed or succumbed to introduced diseases in droves. But they had been living there all along and continue their strong cultural presence in the area.

When Spanish colonists arrived from Mexico (then called New Spain) and began to settle in what is now New Mexico, they named native settlements pueblos, meaning towns in Spanish. They named each pueblo after a Catholic saint, names that persist to this day—e.g., Santo Domingo Pueblo and San Idlefonso Pueblo. The 19 Pueblos in New Mexico are known for their unique culture and art forms. The correct name for the ancestors of the Pueblo people is “Ancestral Pueblo” or “Ancestral Puebloan”.

The Indian Pueblo Cultural Center in Albuquerque serves at the gateway to the 19 Pueblos of New Mexico. It is well worth a visit to their museum, store with pottery and other art from the various pueblos, and a restaurant with native-style food. Their web site explains why the term “anasazi” is no longer appropriate ( It also explains other aspects of Puebloan culture.

In the dry monochrome tan of the desert landscape, the brightly-colored collared lizard is a welcome sight!
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  1. John Monteverdi on June 23, 2022 at 10:14 am

    HI Karen. Really enjoyed reading this. Beautiful pictures. In my class “California Weather Events” we discussed rainfall fluctuations and how they might relate to abandonment of some of the Pueblo sites. I have put the link to the graphic in the Website address below. John

  2. Barbara Sleeman on July 10, 2022 at 1:53 pm

    PBS is looking for you! Great photos and research. Hope you can have the opportunity to do a filmed version of your excursions. Thank you for sharing with all of us.

    • Landscapes Revealed on August 14, 2022 at 1:44 pm

      Thanks Barbara! Not sure I’m ready for that!

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