St. Mary Parish in Westphalia, Michigan

North: Intersection of the western boundary of Clinton County and Dexter Trail in Dallas Township; Dexter Trail southeast to Centerline Road; Centerline Road east to Francis Road.

East: Francis Road south to Cutler Road.

South: Cutler Road west to the western boundary of Clinton County.

West: The western boundary of Clinton County north to Dexter Trail to the point of the beginning.

All Latin Rite Catholics living within the above described territory are considered members of St. Mary Parish, and as such, are subject to the spiritual jurisdiction of the Reverend Pastor of that Parish.