- Natural World
- US EPA - High Environmental School Center
- Chesapeake Bay Foundation
- Sites By and About Governmental Agencies
- Envirofacts
- Fee-based data bases- try Science e-Books and Science Resource Center
- The BUGS Program
- Friends of Assateague State Park
- The Friends of Patapsco Valley and Heritage Greenway
- Hooked on Nature
- The Jones Falls Watershed Association
- Maryland DNR - Stream Monitoring & Aquatic Resources
- The Nature Conservancy in Maryland/District of Columbia
- Patuxent Riverkeeper
- Maryland Sierra Club
- Earth Day 2008
- The Friends of Patapsco Valley State Park
- The Baltimore Sun - current two weeks of The Sun newspaperpaper