One of the largest archeological sites that visitors to the Grand Canyon can explore is located on the Unkar Delta. This large patch of sandy soil is found at a sweeping bend on the north side of the Colorado River at river mile 72.5, downstream from the Tanner Trail and upstream of Unkar Rapid. Its relatively large plain and terraced slopes make it one of the few sites in the Inner Gorge that allowed for significant human occupancy and agriculture.
Unkar is a Paiute word for “red stone,” and the delta is indeed surrounded by vibrant vermilion-colored rocks. The sandy banks were formed by rock debris that Unkar Creek swept down from the North Rim during floods. From around 850 to 1200 A.D., ancestral Puebloans used the area seasonally, planting crops and building homes and granaries on the delta and along Unkar Creek.
Archeologists today believe that Puebloan use of the site peaked around 1100 A.D., but most had migrated away just 100 years later. The original inhabitants farmed on terraces close to the river, but as their population expanded they moved onto higher talus slopes. Life was hard here, with the average life expectancy just 34 years. Buildings were often remodeled and repurposed; over the course of decades one building might be used as living space, storage space, and finally a refuse pit before being abandoned. Farmers constructed terraces that descended the delta in stair steps of irrigated fields and built small ditches to divert the waters of the creek to their crops.
In the late 1960s, archeologists excavated several of the 52 identified sites on the delta. Evidence from such excavations suggests that the population size of the people using the delta increased over time to a point where they could not farm enough food to support everyone.
In February 2010, archeologists from the NPS and Museum of Northern Arizona used GIS to better document and locate the large complex of sites, which will help the park to better manage visitor use of the area and protect its resources.
The Delta is visible from Cape Royal on the North Rim by looking through Angels Window toward the curve in the Colorado River. It is also visible from Lipan Point on the South Rim. Visiting the sites is often a highlight for many river runners, since they can view the foundations of many structures and see artifacts such as pot sherds. The NPS has developed a short walking trail in the area that takes hikers past 10 archeological sites on the Delta.
Many Native Americans see this site as sacred, so visitors are requested to treat it with respect. Federal law prevents disturbance or theft of any artifacts. Leaving items in their place allows archeologists to better study and understand life in the past, and preserves the sites for the enjoyment of future generations.
Written By Sarah Bohl Gerke
- Coder, Christopher. An Introduction to Grand Canyon Prehistory. Grand Canyon Association, 2000.
- Schwartz, Douglas, Richard Chapman, and Jane Kepp. Archeology of the Grand Canyon: Unkar Delta.Grand Canyon Archeological Series, v2. Santa Fe: School of American Research Press, 1980.
- Schwartz, Douglas. On the Edge of Splendor: Exploring Grand Canyon’s Human Past. Santa Fe: School of American Research Pres, 1989.
- Unkar Delta Walking Tour. NPS brochure.