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Find out how you can really keep freedom safe
American Civil Liberties Union (ACLU)
The largest, most influential organization fighting for principles of freedom and the US Constitution. The ACLU has been at the forefront of such issues as abortion rights, freedom of speech, censorship, privacy rights, women's rights, cyber-liberties, drug policy, and the death penalty (to name a few). You can help protect the freedoms you enjoy in the United States by supporting the ACLU.
Join The Nature Conservancy
The Nature Conservancy
The Nature Conservancy is a savy organization that seems to be everywhere. They have been instrumental in preserving many of the few remaining wild places in the US and many other countries. TNC has been responsible for much of the growth of Henry Coe Park in California (one of my favorite places).
The Sierra Club Founded in 1892 by the legendary John Muir and now with more than 700,000 members, the Sierra Club is the grandfather of environmental organizations and ever since Theodore Roosevelt, has had much in the way of political influence in Washington. You can find out why and how to join here.
The Pine Ridge Association This is the volunteer and funding organization for Henry Coe State Park in the San Francisco Bay Area. The association assists park staff in designing interpretive and educational programs and presenting the programs to the public. They are also the major sponsor for the uniformed volunteer training program. The uniformed volunteers are active in all sorts of endeavors at the park, such as greeting the public, trail maintenance, removing barbed-wire, presenting interpretive programs. Here is the PRA's page.