• Fairfax Trails & Streams
  • http://www.fairfaxtrails.org
    
• Great Falls Trailblazers
  • http://www.geocities.com/greatfallstrails/
• Mount Vernon Trail Extension
  • http://www.fairfaxtrails.org/mtvernon/
• Potomac Heritage Trail Association
  • http://www.potomactrail.org/

Trail Maintenance Volunteer Groups

• Potomac Appalachian Trail Club
  • http://potomacappalachian.org
• Great Falls Trailblazers
  • http://www.geocities.com/greatfallstrails/
• Northern Virginia Hiking Club (NVHC)
  • http://www.nvhc.com
• Mid-Atlantic Off Road Enthusiasts (MORE)
  • http://www.more-mtb.org

Hiking Clubs

• Northern Virginia Hiking Club (NVHC)
  • http://www.nvhc.com/
• Potomac Appalachian Trail Club (PATC)
  • http://www.patc.net
• Wanderbirds
  • http://www.erols.com/hcooper/wbirds.htm
• Capital Hiking Club
  • http://www.teleport.com/~walking/chc.shtml
• Sierra Club
  • http://www.sierraclub.org/

Cycling Clubs

• Mid-Atlantic Off Road Enthusiasts (MORE) (off-road cycling)
  • http://www.more-mtb.org
• Washington Area Bicyclists Association (WABA) (on-road cycling)
  • http://www.waba.org

Equestrian

• Clifton Horse Society
• www.CliftonHorseSociety.org/inside.htm
• Hunters Valley Riding Club
  • www.hvrc-va.org

Conservation

• Fairfax ReLeaf
  • http://www.geocities.com/RainForest/5663/
• Northern Virginia Conservation Trust
  • http://www.nvct.org/
• Potomac Heritage Partnership
• Potomac Conservancy
  • http://www.potomac.org/
• Sierra Club
  • http://www.sierraclub.org/
• McLean Citizens Association
  • http://www.mcleancitizens.org
• Difficult Run Community Conservancy
  • http://restonweb.com/community/envirotalk/messages/39.html

Governmental

• Fairfax County Park Authority
  • http://www.fairfaxcounty.gov/parks/cct/
• City of Fairfax Parks and Recreation Advisory Board
  • http://www.FairfaxTrails.com
• Northern Virginia Regional Park Authority
  • http://www.nvrpa.org
• Fairfax County Board of Supervisors
  • http://www.co.fairfax.va.us/gov/bos/homepage.htm
• Nonmotorized Transportation Committee
  • http://www.co.fairfax.va.us/NMTC/
• National Park Service: Potomac Heritage Nat Scenic Trail
  • http://www.nps.gov/pohe

Other

• Reston Paths
  • http://restonpaths.com
• Mapping Services for Sale
  • http://www.windsormapping.com