File:2021 Sivan Vahkih, Casa Grande Ruins, North Facade.jpg
President Benjamin Harrison proclaimed the site to be Casa Grande Reservation on June 22, 1892, becaming the first prehistoric and cultural reserve in the US. President Woodrow Wilson then designated it a national monument on August 3, 1918. The monument is administered by the National Park Service and was added to the National Register of Historic Places in 1966.