Take I-19 south from Tucson. Exit at San Xavier Rd and head west.
Mission San Xavier del Bac, about 9 miles south of Tucson, is a working Mission. Services and special ceremonies are still held for the local population. This mission was completed in 1797 and is currently undergoing restoration. More information can be found on their web site http://www.sanxaviermission.org/Index.html