It takes its name from an earlier mission site founded by Father Eusebio Kino in 1691, which is on the east side of the Santa Cruz River, south of the national park.

The remains of the native settlement are still extant and have been investigated and reported on by archaeologist Deni Seymour.

The later Franciscan mission, which is now a ruin preserved as Tumacácori National Historical Park, was never rebuilt after being abandoned after repeated Apache raids in the 19th century that killed farmers and ranchers in the area and put a stop to the growth of the area's economy.

According to the United States Census Bureau, the Tumacacori-Carmen CDP has a total area of 2.0 square miles (5.1 km2), all land.

Tumacacori has a semi-arid climate (Köppen: BSk) with cool winters and hot summers.

Tumacacori National Park Museum, once used by the Franciscan missionaries in the Mission San José de Tumacácori.