The Stewart’s Cattle Guard Archaeological Site in the San Luis Valley represents a late summer or early fall bison hunting camp occupied by Folsom peoples in the Paleo-Indian period (before 6000 BCE). The site was discovered in the late 1970s and excavated by the Smithsonian Institution’s Paleo-Indian Program from 1981 to 1996, largely under the direction of Margaret A. Jodry. After the Lindenmeier Site, Stewart’s Cattle Guard is the most extensively excavated Folsom site in North America.

Named for its location near a cattle guard along the road between Mosca and Great Sand Dunes National Park in the San Luis Valley, Stewart’s Cattle Guard was discovered after wind erosion exposed bison bones and prehistoric artifacts in the area in the late 1970s. Excavations sponsored by the Smithsonian Institution in 1981 and 1983 revealed that the site was a Folsom campsite and bison butchering station. Between 1985 and 1996, the Smithsonian sponsored nine more field seasons. Nearly 14,000 square feet were excavated, revealing a mass bison kill site dating to before 10,000 BCE.

In her analysis of the excavation, Margaret A. Jodry showed that the site included three spatially and functionally distinct areas: the kill site, the butchering and residential area, and the hide processing area. The kill involved at least forty-nine bison, which the Folsom hunters may have trapped in a sand dune. After the kill, the hunters probably performed preliminary butchering at the kill site before carrying portions of the bison to their nearby camp for further butchering. Hides were processed in a separate area at the southwest corner of the site.

At the residential camp, Jodry identified five separate clusters of burned bone and broken tools where meat processing, food preparation, projectile point production, and other domestic activities occurred. The clusters indicated that the camp was probably composed of between four and seven households, with a total of anywhere from sixteen to forty-nine individuals.

The Folsom hunters apparently performed large-scale bison kills often enough to develop specialized tools and divisions of labor for processing the carcasses. Higher concentrations of certain artifacts at some of the clusters suggested that they may have served as cooperative sites where men or women from several households worked together on specific tasks. Women at the camp probably processed hides to make clothing and tent covers and used ultrathin bifaces to cut strips of meat for drying and storage.

Folsom groups in the San Luis Valley seem to have spent at least part of each year moving quickly from camp to camp in migratory bison hunts. The hunters at Stewart’s Cattle Guard probably stayed at the site for about a week—just long enough to butcher the bison, process the hides, dry some meat, and repair their tools. The messy task of breaking large bones for marrow extraction probably took place throughout the occupation, with a concerted effort to process the remaining bones just before the camp was abandoned.