Osa Peninsula and Corcovado National Park
- Geographic and ecological information on this area of the country, including indigenous species, environmental threats, bibliography, and photos.
- http://www.nmnh.si.edu/botany/projects/cpd/ma/ma18.htm

Nature Conservancy - Osa Peninsula
- Read about the organization's efforts to conserve this lush area of rain forests and complex freshwater and marine ecosystems.
- http://www.nature.org/wherewework/centralamerica/costarica/work/art8689.html

Corcovado Foundation
- Conservation efforts on the Osa Peninsula, assisting directly the administration of Corcovado National Park. Includes projects, information about the area, members and sponsors.
- http://www.corcovadofoundation.org/