NPS Photo

An image of the Casa Grande before 1903.

How was it built?

Father Kino, in 1694, was the first European to call this structure Casa Grande. It is a Spanish word that means 'great house.' The Casa Grande is a 4-story, 11-room structure. It was built about 700 years ago and has been abandoned for about 550 years. It is made of a material called "caliche," which is a type of soil found in the Sonoran Desert. Caliche is a mixture of clay, sand, and calcium carbonate. When it's dry, it is almost as hard as concrete!

Puddling

Archeologists think the Hohokam built the "great house" using a technique called "puddling." They would dig a pit in the ground until they reached the layer of caliche and then would fill up the pit with water. The water would help soften the caliche to form a mud with a dough like consistency. The Hohokam would then carry the mud in baskets to the construction areas. The Casa Grande is made from about 3,000 tons of caliche. That's about six million pounds!

Why was it built?

What did the Hohokam use this building for? Maybe it was a house. Some say it was a temple or maybe a watchtower. It might have been a place for storing seeds and food. Others think it was used as an astronomical observatory where the Hohokam could keep track of the sun, moon, and stars.

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