To support conservation and inspire others to do the same, the Wyss Foundation has pledged $1 million in matching funds to create the Squibnocket Pond Reservation, a rare 304-acre preserve that is now part of the Kennedy family’s Red Gate Farm.

Sheriff’s Meadow Foundation and the Martha’s Vineyard Land Bank announced in September they had reached agreement to acquire the majority of the historic and ecologically diverse Aquinnah estate for $27 million. The sale is expected to close in December.

At time of the announcement, Sheriff’s Meadow said it had already raised $9 million of its $12 million share of the purchase price, and that additional funds were needed to maintain the property.

In a press release this week, Sheriff’s Meadow said Hansjorg Wyss, a Vineyard seasonal resident who is chairman of the Wyss Foundation, agreed to provide the matching grant to help purchase, protect and ensure permanent public access to the land. In 2018, Mr. Wyss created a $1 billion fund called the Wyss Campaign for Nature to accelerate the pace and scale of conservation worldwide.

Red Gate Farm, purchased by Jacqueline Kennedy Onassis in 1978, straddles Moshup Trail and Squibnocket Pond and ranges from beautiful windswept coastal dunes to wetlands, freshwater ponds, forests and salt-blasted heathlands. The Massachusetts Natural Heritage and Endangered Species Program has described the property as one of the most important natural areas in the state.

“To set foot on this property is to be transported to a time before homes and roads dotted Martha’s Vineyard,” Mr. Wyss said in the press release.

Red Gate Farm is now owned by Caroline B. Kennedy and her husband Edwin Schlossberg, who will retain about 95 acres in the center of the property where their homes are located.

The remainder, to be renamed Squibnocket Pond Reservation, includes a mile of frontage on Squibnocket Pond and half a mile of Atlantic-facing beach. Sheriff’s Meadow and the land bank has said it will be open to the public after a yearlong biological study.