Founded on 18 May 1904 by Pope Saint Pius X as the Diocese of Great Falls, a suffragan of the archdiocese of Oregon City, Oregon. Name changed to the diocese of Great Falls-Billings on 14 February 1980. Suffragan of the archdiocese of Portland, Oregon.
- Archbishop Thomas Joseph Murphy
- Bishop Anthony Michael Milone
- Bishop Edwin Vincent O’Hara
- Bishop Eldon Bernard Schuster
- Bishop Mathias Clement Lenihan
- Bishop Michael William Warfel
- Bishop William Joseph Condon