Casa Grande Ruins National Monument

I’m trying to visit a few National Park sites I haven’t seen before on my way to Texas. Even though I live in Arizona there are So many parks I haven’t been to yet and one of them was Casa Grande Ruins National Monument.

Great House Casa Grande Ruins National Monument Arizona

I’ve seen a few Southwest native ruins but nothing built like the “Great House” at Casa Grande National Monument. Almost 1000 years ago the Hohokam people constructed this four story 60 foot long building using subsoil called caliche, a concrete-like mix of sand, clay and calcium carbonate.

Closeup of caliche walls Great House Casa Grande Ruins National Monument Arizona

Imagine the labor involved piling 3,000 tons of caliche mud in successive courses to form walls four feet thick at the base and tapering toward the top. Juniper, pine and fir trees used to form ceiling or floors were carried or floated 60 miles down the Gila River.

Holes in walls line up with solsice Great House Casa Grande Ruins National Monument Arizona

The walls face the four cardinal points of the compass and a circular hole in the upper west wall aligns with the setting sun at the summer solstice. Other openings also align with specific solar and lunar occurrences.  The sky was their calendar.

Ruins around Great House compound Casa Grande Ruins National Monument Arizona

And the Great House is only part of this 2-acre compound surrounded by what was once a 7 foot high wall that contained houses, work areas, courtyards and storage rooms. Plus this is only one neighborhood in a larger community of compounds that covered nearly a square mile housing possibly 30,000 to 60,000 people. The Hohokam were farmers that built the most extensive irrigation ditches lined with caliche from the Gila River and had a lot of mouths to feed.

Great House Casa Grande Ruins National Monument Arizona

When Americans began visiting the area in the late 1800s souvenir hunting threatened to destroy the site. In 1892, Casa Grande became the first archaeological reserve and declared a National Monument in 1918. The Great House has been sheltered since early excavations started in 1903.

Casa Grande Ruins NM Jr Ranger badge & hat pin

How did I learn all this? Well of course, I became a Junior Ranger.

Interpretive sign Casa Grande Ruins National Monument Arizona