» Audubon Naturalist Society - Independent conservation organization serving the Washington D.C. metropolitan region. Find programs, classes, current issues, news, and information about sanctuaries in Maryland and Virginia.

» Audubon Society of the District of Columbia - Field trips, events, birding around D.C., Logan Meadow sanctuary and newsletter articles.

» Biodiversity Database of the Washington, D.C., Area - Searchable database of information and images. Includes organisms and regional nature and preservation areas in the D.C. area.

» Bushmeat Crisis Task Force - Headquarters for consortium of conservation organizations and scientists dedicated to the conservation of wildlife populations threatened by commercial hunting of wildlife for sale as meat.

» Capital River Relief - Coaltion of organizations and individuals focused on cleaning up the Anacostia and Potomac Rivers. Features cleanup schedule, photo gallery, press kit, and FAQs.

» Casey Trees Endowment Fund - A project to restore the tree canopy of Washington, DC, administered by the Garden Clubs of America. Includes a review of the street tree inventory carried out in 2002.

» Cool Capital Challenge - A voluntary program to reduce the DC area's carbon dioxide emissions. Has a carbon footprint calculator, tips, news and resources.

» DC Department of Health - Environmental Health Administration - Works to prevent and control environmentally related diseases while protecting and preserving the ecological system in the district. Features a guide to the bureaus and divisions that make up the Administration.

» DC Greenworks - Non-profit organization supports projects and provides information on low-impact storm water management and urban forestry. Includes information on green roofs, rain gardens, and tree care.

» DC Nature - Photo galleries of DC area wildlife created by a local group of nature photographers.

» D.C. Science Writers Association - An organization of science writers and editors from nearly all the major news outlets in the Washington area that meets monthly for tours, symposia, and professional development.

» DC Urban Gardeners - Nonprofit volunteer organization. Has information on gardening, community gardens, clubs and groups.

» District Department of the Environment - Promotes energy efficiency through conservation, education, and fuel assistance programs and by regulatory intervention. Includes consumer information, a description of agency programs, a guide to resources in its library, an events calendar, and links to related sites.

» Earthquake History of the District of Columbia - Seismic history of DC from the National Earthquake Information Center.

» Flora of the Washington-Baltimore Area - Offers information about flora native to the area. Includes a specimen database, projects, spring flowering records and a gallery.

» FORCE - Friends of Rock Creek's Environment - Nonprofit organization promotes a healthy and sustainable Rock Creek watershed. Has news, information and links.

» Friends of the Earth DC Environmental Network - A consortium of conservation organizations that meets regularly to focus on environmental problems specific to the region, exchange information, and coordinate strategies. Includes background documents [PDF].

» Green DC - DC government site has information on local environmental issues and government programs.

» HowStuffWorks: Exploding Manholes - Information on the frequent mishaps under the streets of the city.

» Maryland-National Capital Park and Planning Commission - Acquires, develops, maintains and administers a regional system of parks in Montgomery and Prince George's Counties in Maryland.

» The Nature Conservancy - Maryland/District of Columbia - Works to protect critical natural lands. Features places protected, events, news and volunteer opportunities.

» Pre-Columbian Society of Washington, DC - Promotes interest in Pre-Columbian cultures through annual symposia, monthly meetings, and a newsletter. Includes newsletter index.

» Sierra Club: Washington, DC Chapter - News and issue information from the local chapter of the environmental organization.

» Washington Regional Network for Livable Communities - Advocates "smart-growth" transportation investments, land use policies, and community designs. Includes newsletter archive and policy documents.