Sierra ClubThe Sierra Club is the largest and most influential grassroots environmental organization in the United States, working for more than 130 years to promote clean energy, safeguard public health, protect wildlife, and preserve remaining wild places through activism, education, lobbying, and legal action. It operates through 64 local chapters and mobilizes volunteers to take action on climate, conservation, and public lands, offering programs such as local campaigns, outdoor outings, and Sierra Magazine. The group advocates to defend public lands from privatization and development and to advance renewable energy and environmental justice, funding its campaigns through memberships and donations.