Tumacácori Mission, Spanish colonial mission ruins in Santa Cruz County, US

Tumacácori is a Spanish Colonial mission site near Nogales, Arizona, in Santa Cruz County. The present church was begun in 1800 with five-foot-thick cobblestone foundations and adobe walls raised about seven feet before funds ran out; work resumed in 1821 under Juan Bautista Estelric and Ramón Liberós. The bell tower was never capped with its dome. The site lies within Tumacácori National Historical Park, 360 acres (1.5 km2) in three separate sections.

Jesuit priest Eusebio Kino founded the first mission in 1691, beginning European settlement in this region. The mission expanded and changed over two centuries, reflecting the long period of Spanish and later Mexican colonial control.

The site reflects how O'odham people and European missionaries shaped each other's lives over centuries through shared settlement and religious practice. Walking through the ruins, you see how two worlds met in the architecture and daily arrangements of the missions.

The grounds are accessible via paved paths with a museum displaying colonial period artifacts and guided tour options available. You can choose between shorter walks and longer routes depending on your fitness level and how much time you want to spend exploring.

The church begun by Franciscans in 1800 was never finished: its bell tower lacks the dome that was planned. Five-foot-thick cobblestone foundations were laid, then work stopped when funds ran out, leaving walls only seven feet high for years. The O'odham name Cemagĭ Gakolig means "crooked limestone place".