A sweeping conservation initiative announced Monday will preserve nearly all the remaining undeveloped land on Cuttyhunk — including a large swath of unspoiled barrier beach, salt marsh and coastal upland — on the tiny island at the tip of the Elizabeth island chain.

The public-private partnership will place 68 acres under permanent protection, in tandem with the donation of a conservation restriction on a separate 250-acre parcel at the remote, unspoiled west end of Cuttyhunk.

The properties will remain open for public use.

The Buzzards Bay Coalition, town of Gosnold, commonwealth of Massachusetts, U.S. Fish and Wildlife Service, the Bouchard 120 Oil Spill Natural Resources Damages Trustee Council and 198 private donors all contributed to the $6.1 million acquisition, according to a press release.

The property had been on the market for potential development.

All told, the acquisition will protect more than 300 acres of land and more than five miles of Massachusetts coastline.

“Protecting and permanently preserving such a significant portion of Cuttyhunk is a truly historic achievement for the long-term protection of Buzzards Bay,” said Buzzards Bay Coalition president Mark Rasmussen in the release. “This is one of our region’s most unique landscapes.”

The land was owned by descendants of William Wood, the turn-of-the-century industrialist who bought much of the land on Cuttyhunk beginning in 1905. Mr. Wood built the island’s two great houses — Avalon and Winter House. “As stewards of much of the undeveloped land on Cuttyhunk, and following in the tradition of our great-grandfather, William Wood, who established our family’s foothold on Cuttyhunk, we are proud to participate in this preservation plan of our beloved island,” said Van Spaulding, in a statement on behalf of the family.

The 68 acres include Barges Beach, the scenic Lookout and Bayberry Hills, a portion of Copicut Neck — all of which will be owned and managed by the Buzzards’ Bay coalition — and Church’s Beach, which will be owned by the town of Gosnold. All the properties will be managed as public reserves, ensuring public access.

“Days spent swimming, picnicking, and fishing at Barges and Church’s beaches and walks up to the stunning views from the top of Cuttyhunk’s highest points will remain forever part of life on Cuttyhunk,” the press release said.

The acquisition earned praise from a wide array of state and federal officials, including Massachusetts Sen. Elizabeth Warren, Cong. Bill Keating, the Cape and Islands state legislative delegation, Gov. Charlie Baker, U.S. Fish and Wildlife and the Gosnold selectmen.

Beyond public access and recreation, the two beaches bookend the island’s federally recognized harbor of refuge, an important navigational feature at the entrance to Buzzards Bay, the press release said. The protected land will also preserve water quality in the bay and protect the island’s only public drinking water supply, as well as protecting the unique maritime island ecosystem.

Earlier this year, the state awarded $1.4 million for the project through the Municipal Vulnerability Preparedness (MVP) Action grant program, which aims to strengthen coastal resilience in the face of climate change and rising sea levels.

Two large federal grants — $1.15 million from the Bouchard 120 Oil Spill Trustee Council and $1 million from the federal U.S. Fish and Wildlife Service National Coastal Wetlands Conservation Grant Program — focused on preservation of habitats and wildlife.

The Bouchard oil spill occurred in April 2003 when a tank barge struck the rocks south of Westport after passing on the wrong side of a navigational marker at the entrance to Buzzards Bay. The accident released nearly 100,000 gallons of fuel oil in Buzzards Bay.

“Protecting Cuttyhunk island is a fitting way to help offset the 2003 oil spill, which coated the island’s shores,” said U.S. Fish and Wildlife Service regional director Wendi Weber in the release.

In the spring of 2019, voters at the Gosnold town meeting unanimously approved contributing $400,000 to the project.

The project was also awarded a $400,000 state L.A.N.D. (Local Acquisitions for Natural Diversity) grant, a $300,000 state grant to guard the public drinking water supply on the island and a municipal mini-grant from the Buzzards Bay National Estuary Program, a joint program of the Massachusetts Office of Coastal Zone Management and the U.S. Environmental Protection Agency.

The Massachusetts Department of Conservation and Recreation (DCR) helped to coordinate one of the large federal grants, and technical support was provided by the Martha’s Vineyard Commission.

Completing the fundraising was $1.4 million in private donations from 198 Cuttyhunk residents.

The Buzzards Bay Coalition will manage and care for the land. Trails will be improved over the winter with an expected reserve opening in 2021.