Laurance & Mary Rockefeller Frederick Billings’ granddaughter, Mary French, grew up spending summers on the estate. In 1934 she married Laurance Spelman Rockefeller, one of the five sons of John D. Rockefeller Jr. Together they cherished the Woodstock estate, and sustained it through the twentieth century. The Rockefellers made many historically sensitive improvements to the mansion, grounds, and farm. Generous benefactors, they were involved in progressive business ventures in the community.
Laurance Rockefeller [1910-2004] applied the human values of stewardship to further the goals of conservation, outdoor recreation, and environmental protection in private and public arenas. He was a valued collaborator with Lady Bird Johnson on beautification campaigns nationwide in the 1960s. Rockefeller was a key supporter of the national parks, as his father had been before him. He was awarded the Congressional Gold Medal in 1991 for his contributions to conservation and historic preservation.

In 1992 the Rockefellers gave the Mansion and grounds and the 550-acre forest on Mount Tom in Woodstock to the nation, to become Marsh-Billings-Rockefeller National Historical Park.