Environmental Resources
- The Earth Charter Initiative
- Environmental Defense
- Friends of the Earth
- Greenpeace USA
- Grist: Environmental News & Commentary
- Izaak Walton League of America
- Keep America Beautiful
- League of Conservation Voters
- Living on Earth
- National Audubon Society
- National Environmental Trust
- NPR: Environment
- National Wildlife Federation
- Natural Resources Defense Council
- Nature Conservancy
- Rails-to-Trails Conservancy
- Republicans for Environmental Protection
- Sierra Club
- Sustainable Communities Network
- SustainUS
- United Nations Environmental Programme
- Wilderness Society