Cerro de Trincheras in the San Simon Valley

The San Simon Valley has been a cross roads for a number of cultures and evidence of their occupation can be found along the length of the valley. One of the more enigmatic and less understood sites found in New Mexico, Arizona, and northern Mexico are walled hilltops. These Cerro de Trincheras or fortified hills were first recognized in the late 1800's. The best known and investigated of the Trincheras is Cerro de Trincheras, located in northern Sonora Mexico. The site can be seen from over 25 miles away, is composed of over 900 north facing terraces, and was occupied between 1300-1500 CE. Of those sites analyzed, occupation of the Trincheras occurred in 3 phases. The oldest site was occupied about 1000-800 BCE, then several from a period of around 200-500 CE, and a final phase of construction and occupation around 1300-1500 CE. The Trincheras phenomena are not isolated temporally or spatially occurring over a period of 2500 years and over an area of 50,000 square miles. As such they may represent the work of the local agrarian peoples. The function of these sites is somewhat controversial but the it has been suggested that they served as:

1. Refugia created by the locals to protect their harvests from other groups.
2. Village sites.
3. Communication centers, based on hilltop locations.
4. Specialized centers for public events and ceremonies.
5. Terraced gardens.

While Arizona and Mexico have the highest density of Trincheras, several are known from New Mexico. This site was discovered on a flight from the Sky Gypsies complex at Amigos del Cielo airpark, aerial photograph 1. The hill rises 20 meters from the surrounding valley floor and the walled hilltop has a well defined outer wall and fainter inner wall, aerial photographs 2 and 3 . The outer oval wall encloses an area 68 x 52 meters, while the inner circle is about 30 meters in diameter. Inside the inner wall there are at least a dozen round rooms discernible, some created using existing rock outcrops, aerial photograph 4.

Who was responsible for the construction of this particular Trincheras and its function await further archeological studies.

Aerial photograph 1

Aerial photograph 2

Aerial photograph 3

Aerial photograph 4

Click to enlarge

Aerial photographs of other Trincheras may be found here and here. A description of Cerro Juanaquena a Trincheras site in northern Mexico may be found here.