St. Sebastian Parish is a member of Region VIII and Deanery 5 in the Diocese of Greensburg. Msgr. Michael W. Matusak, vicar forane, pastor of St. Therese, Little Flower of Jesus Parish, Uniontown and administrator of St. Joseph Parish, Uniontown; St. Hubert, Point Marion; SS. Cyril and Methodius Parish, Fairchance; and Holy Family, West Newton, serves as the dean of Deanery 5.​​ Listed below are the parishes that make up Region VIII, all of which are located in Fayette and Westmoreland counties.