‘Pure Americana’: the Cape Cod house that Bunny Mellon built
When William I. Koch bought the estate in Oyster Harbors a dozen years ago, he vowed to preserve the Bunny Mellon Style — now entrenched in American folklore — ‘the way I remember it when I used to visit’. It is now offered through Christie’s International Real Estate
The Kennedys were among the many illustrious visitors to the property, one of the finest in the private Cape Cod enclave of Oyster Harbors. Photo: Halsey Fulton
In 2013, the billionaire businessman, philanthropist and collector William I. Koch was able to purchase a property that he had admired for 40 years: 17 Indian Trail, Osterville, Massachusetts. The inconspicuous address belies one of the finest estates in Oyster Harbors, an exclusive enclave on a private island off the southern shores of Cape Cod.
Sitting on a 7.4-acre plot, the 7,300-square-foot New England-style house features eight bedrooms and nine bathrooms. Around the grounds are two cottages, an artist’s studio, a tennis court, a greenhouse, orchards and more than 500 feet of private waterfront with a beach house and dock.
Over the decades, the home has hosted titans of industry, Hollywood stars and world leaders. Now, this legacy property is listed once more, with an asking price of $23.85 million through Christie’s International Real Estate.
Built of concrete to withstand the salt air, the house is clad with wooden shingles in the traditional New England style. Photo: Halsey Fulton
Koch acquired the estate from Rachel Lambert ‘Bunny’ Mellon, one of America’s greatest tastemakers and the designer of the White House Rose Garden. It’s located on Oyster Harbors — a gated community only accessible from the mainland by drawbridge — which features a marina, an 18-hole golf course and a historic country club.
The house sits on one of several local parcels of land acquired from the 1950s onwards by Bunny and her husband, the banking heir and thoroughbred racehorse breeder Paul Mellon. Among the others was Dead Neck Island, a 1.7-mile uninhabited sandbar between Grand Island and Nantucket Sound, which is now a nature reserve.
After designing the elegant house, Bunny dressed it in a delightfully rustic manner, with checkerboard painted floors, blue-and-white china, wooden model ships, antique duck decoys and traditional quilts. Elle Decor called it ‘Pure Americana’.
The property features two guest cottages, an artist’s studio, a beach house and a greenhouse, in addition to extensive gardens reflecting Bunny Mellon’s horticultural interests. Photo: Halsey Fulton
Outside, she created wildflower meadows overflowing with colour, laid out vegetable patches and set flagstones wide enough apart so that wild plants could spring up between them. Every summer, her beloved collection of citrus trees would be shuttled to Cape Cod from her winter home in Antigua.
Overall, the estate’s bucolic charm echoed Bunny’s mantra that ‘nothing should ever be noticed’ — and helped establish a look now known as the ‘Bunny Mellon Style’.
Meryl Gordon’s Bunny Mellon: The Life of an American Style Legend includes a typical Sunday lunch guest list at the house: the actor Frank Langella; the dancer and sister of Fred Astaire, Lady Charles Cavendish; the playwright Sir Noël Coward; and the Mellons’ close friends, John F. and Jacqueline Kennedy.
The sitting and dining rooms face Nantucket Sound. Photo: courtesy of William I. Koch
Koch first visited the house in the 1970s, sharing with Bunny and Paul his love of fine wine. (In June 2025, The Cellar of William I. Koch realised $28.8 million at Christie’s in New York, making it the largest single-owner wine collection ever sold in North America.)
The Mellons in turn introduced Koch to some of the thousands of works of art they owned. ‘[They] had some of the world’s greatest masterpieces,’ Koch recently told the Wall Street Journal. ‘I always wanted a Van Gogh, and Paul knew it, and would always — with just a touch of smugness — steer me into the room where it hung.’
They also bonded over a love of sailing. Bunny’s father, the great advertising man Gerard Lambert, was a key player in several winning campaigns for the America’s Cup, which Koch himself would come to lift in 1992.
The estate has more than 500 feet of waterfront, a dock and access to a private island, now serving as a protected bird sanctuary. Photo: courtesy of William I. Koch
Koch bought the house and 26 acres from Bunny in 2013. Not long afterwards, he purchased an adjoining acre of land that she had gifted to a sailing companion, in order to create a private compound.
Since then he has retained the charming appeal of the house, using it to accommodate visitors to his primary Cape Cod residence nearby. ‘It is important to me to preserve the home the way I remember it when I used to visit Paul and Bunny, and to maintain their influence and style over the estate,’ Koch told the New York Post.
‘My main Cape home is next door — it is plenty big for my friends and family now,’ Koch explained to the Wall Street Journal of his decision to sell the Mellons’ former house. ‘It is time for someone else to enjoy this marvellous property.’
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