Tumacácori National Historical Park is located in the upper Santa Cruz River Valley in Santa Cruz County, southern Arizona. The park consists of 360acre in three separate units. The park protects the ruins of three Spanish mission communities, two of which are National Historic Landmark sites. It also contains the landmark 1937 Tumacácori Museum building, also a National Historic Landmark.HistoryThe first Spanish Colonial Jesuit missions in the locale were established in 1691, Mission San Cayetano de Tumacácori (at Tumacácori) and Mission Los Santos Ángeles de Guevavi, are the two oldest missions in southern Arizona. The Franciscan church of Mission San José de Tumacácori, across the river from and replacing Mission San Cayetano de Tumacácori, was built in the 1750s. The third mission was established in 1756, Mission San Cayetano de Calabazas. The Mission San José de Tumacácori complex is open to the public. Nearby are the park's visitor center and the Tumacácori Museum in a historic Mission Revival style building. The Guevavi and Calabazas missions are not open to the general public, but can be visited on reserved tours led by park staff.The Tumacácori missions complex was originally protected as Tumacácori National Monument, in 1908 by President Theodore Roosevelt. It was listed on the National Register of Historic Places on October 15, 1966. In 1990 the national monument was redesignated a National Historical Park. The Guevavi and Calabazas mission units were added to the Tumacácori missions complex unit, within the new Tumacácori National Historical Park.