| 21CSC Org Name | Year Approved as 21CSC Member |
| Bob Marshall Wilderness Foundation | 2014 |
| Montana Conservation Corps* [Accredited Corps] |
2013 |
| Montana Discovery Foundation | 2014 |
| Montana State Parks AmeriCorps | 2013 |
| Montana Wilderness Association | 2013 |
| National Center for Appropriate Technology | 2016 |
| National Forest Foundation | 2014 |
| Society for Wilderness Stewardship | 2016 |
| Watershed Education Network | 2013 |
| Western Transportation Institute – Public Lands Transportation Fellows Program, Montana State University | 2017 |
| Wilderness Institute | 2013 |
| Yellowstone Youth Corps | 2014 |
*= Accredited Corps:
The Accreditation process is overseen by the Corps Center of Excellence, a subsidiary of The Corps Network; the National Association of Service and Conservation Corps. Accreditation is granted to Corps that have undergone an in-depth review of their general operations, financial management, risk management, and governance standards and have demonstrated accountability to both Corpsmembers and the communities in which they operate. Accreditation is available only for organizations that meet the definition of a Corps.
