El Cóporo's active period dates from between the years 1 and 1000 AD, reaching its peak between 400 to 600 and declining between 900 to 1000. It is located within the area of the Tunal Grande, delimited to the west by San Luis Potosí, the Jalisco Mountains, Zacatecas, Aguascalientes, and to the northeast by Guanajuato. In the sixteenth century, the Spanish named it El Cóporo (“the great road”) due to its abundance of prickly pear cacti.
The settlement’s location was decisive in its development. As well as being made up of grasslands and mountains, it is found between the Cóporo and Gotas rivers and protected by two canyons.
This archeological area, which is oriented towards the west, is distinguished by its earthen architecture such as its adobe walls, flat mud roofs and wattle and daub structures. The topography was exploited in building the structures, using rocky outcrops for the structures and staircases. The ground was leveled using a system of terraces in order to achieve the stability necessary for building.
The Llano Complex is located at the foot of the hill in the lower section, an area which was surrounded by rooms. Here, two adobe fireplaces, milling instruments and pots were found. At the peak, the ceremonial Cóporo Complex is located; the natural surroundings were exploited to make this a sacred space. Finally, in the vicinity of the hill is the Gotas Complex, where archeologists found a shrine.
Most notably in the staircases, petroglyphs are visible with geometric designs and animal symbols. Circular spirals (linked to water) and quadrangular spirals (linked to fire) both appear frequently. The petroglyph in the Cóporo Complex is also very noteworthy. It consists of a triangular spiral pointing to the north, which suggests that the settlers carefully observed the movements of the sky.
