Officially Sanctioned Region
- Big Horn
- Carbon
- Carter
- Custer
- Dawson
- Fallon
- Garfield
- Golden Valley
- Judith Basin
(southern half) - McCone
- Meagher
- Musselshell
- Park
- Petroleum
- Powder River
- Prairie
- Richland
- Rosebud
- Stillwater
- Sweetgrass
- Treasure
- Wheatland
- Wibaux
- Yellowstone