The Diocese of Helena has maintained a mission presence in Guatemala since 1964. The mission lies in the coastal highlands of Guatemala, about 100 km (66 miles) west-northwest of Guatemala City, not too far north from the City of Mazatenango.

The complex contains a residence for the four Guatemalan priests who serve the parish; a residence for the Clinic Coordinator; accommodations for volunteers and visitors who serve there; a medical clinic; and facilities attendant to all these functions. La Asuncion School is about 3 miles from the central complex. Santo Tomas Apóstol Church, the center of the parish community, is only a few blocks away.

The operation of the mission in Guatemala and its various projects is dependent upon both contributions to the Annual Catholic Appeal and on special donations. Anyone wishing to make a contribution to the work of the mission is encouraged to do so.