[2] In 1969, Margaret Rockefeller learned from the staff at Acadia National Park that conservation easements could be used to protect the natural scenery of islands in a portion of the Gulf of Maine from Penobscot Bay to Schoodic Point.
With the encouragement of her husband, David Rockefeller, and participation by Thomas Dudley Cabot, Margaret Rockefeller formed the nonprofit Maine Coast Heritage Trust in 1970 to assist island owners who might choose to donate conservation easements to Acadia National Park.
In the first year of operation, thirty conservation easements were donated by island-owners to Acadia National Park.
[4] The MCHT subsequently formed alliances with additional public and private organizations and expanded its activities to include the entire Maine Coast.
[6] On the 50th anniversary of the Maine Coast Heritage Trust in 2020, it listed 329 whole islands protected by conservation easements and 148 preserves available for public access, a combined total of 156,000+ acres including 99 miles of trail.