The Association for the Study of Literature and Environment (ASLE) - is the definitive site for those interested in pursuing the relationship between human beings and the natural world through
literature.

The Thoreau Institute features the world's foremost collection of Thoreau and Thoreau-related materials, a state-of-the-art archives and technology center, a spacious reading room, a variety of educational programs and resources.

The American Society for Environmental History (ASEH)
promotes research, teaching and publication in the field of environmental history, with special attention given to fostering a dialogue between the humanities and sciences.

The Orion Society Premier publisher, offering teacher training opportunities, curriculum materials and conferences.  Publishes Orion Magazine, a blend of science and the arts, that has been called "America's Finest Environmental Magazine" by The Boston Globe.

The Blue Ocean Institute  provides accessible and reliable information for making personal choices that help restore living abundance in the oceans.  The Blue Ocean Institute is founded on three interrelated areas: scientific generation of new information; translation of science into practical advice for use in peoples' daily lives; and inspired writings about the magnificence of the sea and its creatures.

Society of Environmental Journalists'  mission is to advance public understanding of environmental issues by improving the quality, accuracy and visibility of environmental news reporting.

Envirolink is an international organization that acts as an environmental information clearinghouse.  Provides excellent search tools and a comprehensive listing of environmental organizations.