Tucson Origins

Archaeology Southwest has a long-term commitment to the archaeology and history of our home community. In the 1990s, we conducted a series of small excavations to locate buried adobe walls of the Tucson Presidio. Beginning in 2000, we played a role in the Tucson Origins Project funded by Tucson’s Rio Nuevo Project.

The Original Tucson: A 4,000-year Agrarian History

Tucson is one of the longest continuously occupied places in the United States. More than 4,000 years ago, the first inhabitants settled near the base of today’s “A” Mountain (Sentinel Peak), lived in small pithouses, and grew crops of maize in the Santa Cruz River floodplain. Irrigation canals in the floodplain have been dated to 3,500 years ago.

Although the adoption of agriculture is often described as a “revolution” in the way humans make a living, the evidence from Tucson indicates that change was more gradual. For example, several kinds of small, fired-clay items were produced between 2,000 B.C. and A.D. 50, but production of ceramic containers did not begin until after A.D. 50. At that time, large jars began to be used for food storage instead of the deep earthen pits that were so common previously.

The Hohokam Culture thrived for at least a millennium—about A.D. 450 to 1450. These people farmed corn, beans, squash, and cotton in the Santa Cruz floodplain and many of its tributaries. When Father Kino visited the Tucson area in 1694, he was greatly impressed with the fields he saw at San Xavier del Bac, and commented that they could support a population the size of Mexico City. By the mid-1700s, European missionaries living in the region had introduced wheat and barley to the agrarian mix.

Recent research in anticipation of development projects and Tucson’s Rio Nuevo Project has provided a wealth of new information about Tucson’s 4,000-year agrarian history.

El Presidio Real de San Agustín del Tucson

During the 1990s, Center staff worked with the Tucson Presidio Trust, the University of Arizona, and the City of Tucson to search for buried remnants of the Presidio Wall beneath the concrete and asphalt of downtown Tucson. Ground-penetrating radar yielded images that stimulated multiple rounds of small-scale excavations funded by the City of Tucson, Pima County, and grants from the Arizona Humanities Council. The excavations established that preservation was far greater than had been expected.

During the Rio Nuevo Project, also funded by the City of Tucson, the northeast corner of the Presidio was exposed. It was shown to overlie both a thousand-year-old pithouse village and an even earlier village from about 2,000 years ago.

Rio Nuevo also funded a reconstruction of the northeast corner of the Presidio. This park is open daily and is free. On many weekends, volunteers from the Tucson Presidio Trust provide living history demonstrations.

Downtown Archaeology

The original Tucson townsite was laid out as two square miles in 1878, two years before the arrival of the railroad. Since then, Tucson has grown to encompass more than 195 square miles. The downtown area in particular has undergone several episodes of re-development, often preceded by archaeological investigations. As a result, the archaeology of Tucson’s first fifty years as a city has been documented in numerous locations.