Casa Grande Ruins National Monument in Arizona Preserves Hohokam Ruins

The first archaeological site in America to be protected by the United States government, Casa Grande Ruins is located in the flat plain of Central Arizona, situated between the Gila and Santa Cruz Rivers near the towns of Coolidge and Casa Grande. Designated an "archaeological reserve'' in 1892 and a national monument in 1918, the centerpiece of Casa Grande is a 4-story structure that dates from the late Hohokam period, probably around the 14th century.

The ruin, often referred to as the "Great House'' or "Big House'', sits on flat terrain and is protected by a metal canopy that deflects the bright sun and heat of this portion of Arizona, where temperatures often soar to above 80 degrees during the winter and 110 in the summer. The purpose of the building itself is a mystery, though some believe it may have been an astrological observatory due to the way the building is positioned and aligned with the moon and sun. It measures about 60 feet by 40 feet and had walls that were more than a meter thick. Wooden beams supported the walls and staircases are visible inside. The exterior was fashioned from a material known as caliche, which is a naturally-occurring soil made of clay, sand, and calcium carbonate, typically found in the deserts of the American Southwest. Many of the Native American tribes in the region used caliche to build their structures.

Because Casa Grande is a protected ruin in very fragile condition, visitors are not permitted to go inside. However, guests can explore the Big House from the outside, where much is visible, and visitors are welcome to photograph the ruin from fairly close proximity. Guided tours at the site of the ruins are available during the winter months, from December through April, and are conducted by National Park rangers. Schedules vary and reservations are not necessary.

A Visitor Center near the entrance to the park is home to a small museum that includes artifacts and information about the Hohokam culture, one of four major prehistoric archaeological traditions of the American Southwest, particularly the Phoenix Basin. The Visitor Center also includes a small bookstore and a restroom area. Children who wish to participate in the Junior Ranger program may pick up information at the Visitor Center on how they can earn a badge for their visit to Casa Grande Ruins National Monument. A picnic area with shade is available across the parking lot from the center and provides visitors with a view of an onsite ancient ball court.

Beginning in 2009, an annual American Indian Music Fest will be held each February at the Casa Grande Ruins National Monument, featuring three days of American Indian music, dance, storytelling, art, and food.