Washington, D.C. has been the most active city in the country for Conservation Easement programs and is served by three principal easement organizations, all of which have proven records of affirmative enforcement and each of which have operated in the city for more than thirty years:

The L'Enfant Trust
The L'Enfant Trust with the largest portfolio in the country, holds easements on properties citywide; and

The Foundation for the Preservation of Historic Georgetown
The Foundation protects many fine Georgetown properties; and

The National Trust for Historic Preservation
NTHP, which generally seeks to protect properties of national significance, holds a few local easements mostly acquired in decades past.

Also listed on the DCHPO Website:
Capitol Historic Trust, Inc., first incorporated in Maryland in 2003 as "Tri-State Architectural Trust, Inc." and then registered three years later, in 2006, in the District of Columbia. CHT holds a number of D.C. easements and according to its website relies on "local ordinances" for preservation enforcement and sees itself, in the words of its President, "primarily as an insurance policy for those cases which will need our attention in the future."

American Easement Foundation, incorporated in Virginia in 2000 and according to its website operates nationally.