M
| Maiden | Missoula |
| Malta | Mocassin |
| Manhattan | Monarch |
| Marysville | Mondak |
| Medicine Lake | Montague |
| Melstone | Moore |
| Miles City | Musselshell |
| Montana Historical Society Research Center |
| 225 North Roberts, P.O. Box 201201, Helena, MT 59620-1201, 406-444-2681, 406-444-2696 (fax). |
| mhslibrary@mt.gov |