| Maryland Alliance for Greenway Improvement and Conservation | MD |
| Maryland Native Plant Society | MD |
| Maryland PIRG | MD |
| Maryland United for Peace and Justice | MD |
| Massachusetts Audubon Society | MA |
| Massachusetts Society for the Prevention of Cruelty to Animals | MA |
| Michigan Environmental Council | MI |
| Michigan Humane Society | MI |
| Michoacan Reforestation Fund | KS |
| Minnesota Native Plant Society | MN |
| Minnesota River Valley Audubon Chapter | MN |
| Missouri Botanical Garden | MO |
| Montana Audubon | MT |
| Montana Wilderness Association | MT |
| Morris Arboretum of the University of Pennsylvania | PA |
| Mount Graham Coalition | TX |
| Movement for a People's Party | CA |
| Naropa University | CO |
| National Association of Biology Teachers (NABT) | VA |
| National Association of People with AIDS | MD |
| National Audubon Society | DC |
| National Humane Education Society | WV |
| National Recreation & Parks Assoc | VA |
| National Wildlife Refuge Association | DC |
| National Wolfwatcher Coalition | MN |
