Mission San Xavier del Bac is a historic Spanish Catholic mission located about 10 miles (16 km) south of downtown Tucson, Arizona, on the Tohono O'odham Nation San Xavier Indian Reservation. The mission was founded in 1692 by Padre Eusebio Kino in the center of a centuries-old settlement of the Sobaipuri O'odham, a branch of the Akimel or River O'odham located along the banks of the Santa Cruz River. The mission was named for Francis Xavier, a Christian missionary and co-founder of the Society of Jesus in Europe. The original church was built to the north of the present Franciscan church. This northern church or churches served the mission until it was razed during an Apache raid in 1770.

Tucson is a city in and the county seat of Pima County, Arizona, United States, and is home to the University of Arizona. It is the second-largest city in Arizona behind Phoenix, with a population of 542,629 in the 2020 United States census, while the population of the entire Tucson metropolitan statistical area (MSA) is 1,043,433. The Tucson MSA forms part of the larger Tucson-Nogales combined statistical area. Both Tucson and Phoenix anchor the Arizona Sun Corridor. The city is 108 miles (174 km) southeast of Phoenix and 60 mi (100 km) north of the United States–Mexico border.