Rocky Mountain Regional Detention Facility
Rocky Mountain Regional Detention Facility
Regional / Contract Detention FacilityMailing Address
[Detainee Full Name] — [ID if known]
Rocky Mountain Regional Detention Facility
P.O. Box 930
Hardin, MT 59034
Rocky Mountain Regional Detention Facility
P.O. Box 930
Hardin, MT 59034
Physical Address
1015 N. Lessard Avenue, Hardin, MT 59034
Governing Agency
Big Horn County / Contract Detention Operations
Inmate ID
Inmate / Booking ID — Not required
Last Verified
September 27, 2026
Facility Mailing and Service Information
Use the detainee's full name and ID if known. Verify the current Rocky Mountain Regional Detention Facility mailing and acceptance rules before sending correspondence.
Last verified: September 27, 2026
Verify current photo size, quantity and content restrictions before sending photographs.
Last verified: September 27, 2026
Verify current book, publication and package rules before sending.
Last verified: September 27, 2026
Do not mail cash unless explicitly permitted. Use the facility's current approved inmate-account deposit method.
Last verified: September 27, 2026
Verify current visitor approval, identification and scheduling requirements before travel.
Last verified: September 27, 2026
How to Address Your Letter
Use the detainee's full name and ID if known. Verify the current Rocky Mountain Regional Detention Facility mailing and acceptance rules before sending correspondence.
About Rocky Mountain Regional Detention Facility
Rocky Mountain Regional Detention Facility is a regional detention facility in Hardin, Montana.