Organizations

The following is a list of prominent BDSM organizations in the United States.

The Eulenspiegel Society, founded in New York City in 1971, is the oldest SM support group in the US.
The Society of Janus, founded in San Francisco, California in 1974, is the second oldest SM support group in the US.
The BackDrop Club, founded in San Francisco, California in 1966 - also maintains the SM-201 Wiki which has FAQ, Resources Guide, and History sections
Tampa Bay Bondage Club, Gay men's SM club and support group.
The Threshold Society, formerly the Los Angeles chapter of The Society of Janus
The Wet Spot is a non-profit, membership-based "sex-positive community center" in Seattle, Washington.
Black Rose, an alternative sexuality support group for the area around Washington, DC. It is BDSM friendly.
Impact of Memphis, West Tennessee/The Mid-South's Premier BDSM Club/Dungeon Space since 1998. They also have a Fetlife Group if you'd like to join them there.
Conversio Virium, Columbia University student organization for BDSM.