Casa Grande Ruins National Monument preserves a major Hohokam settlement in Coolidge, Arizona, dating from about 1150 to 1450 CE. Its centerpiece, the Casa Grande or Big House, is the site’s largest surviving structure, a multi-story caliche adobe building that reflects the engineering of a Sonoran Desert society sustained by irrigation agriculture and far-reaching trade. The enclosed compound also once included other structures and a ball court. Seen by Father Eusebio Kino in 1694, the ruins later became an early focus of U.S. preservation: protected as Casa Grande Reservation in 1892, redesignated a national monument in 1918, and further sheltered and maintained through twentieth-century preservation work.