The Sobaipuri was a Piman Indian tribe that inhabited the main and tributary valleys of the San Pedro and Santa Cruz rivers. This tribe no longer exists. Missions were established among them by the Spaniards in the later part of the 17th and beginning of the 18th century. San Xavier del Bac was one of the missions established for this tribe. The remnant of this tribe was absorbed into the Tohono O'Odham.
Handbook of American Indians north of Mexico. Hodge, Frederick Webb. Ed.