| Name | Deductibility Code |
| American Legion Post Joe Nowacki | 6 |
| Lost Rivers Medical Center Foundation | -- |
| Mackay Cultural and Arts Council Inc. | -- |
| Mackay School District 182 Education Foundation | -- |
| Mackay Senior Citizens Inc. | -- |
| North American Moose Foundation Inc. | -- |
| South Custer County Historical Society Inc. | -- |
| Veterans of Custer County Memorial Inc. | -- |
| White Knob Historical Preservation Committee Inc. | -- |