The ultra-luxe real estate market has been notoriously booming this year, with an influx of listings and sales at or above the $100 million mark. Now, one seller is hoping to one-up that state’s record of $120 million, listing a 63-acre island estate on Long Island Sound for $175 million. It would also be the most expensive sale in U.S. real estate history. The current national record-holder is a Hamptons home that cost hedge fund manager Barry Rosenstein $147 million in 2014.

Located about 50 miles from New York City with a Darien, Connecticut zip code, the estate is known as Great Island. Its early 1900s-built main home—originally dubbed Villa Juliette—is made of stone and features a tiled roof. It includes six bedrooms in addition to guest and staff wings, as well as views of the sound from nearly every room.

Other structures included in the sale: a boat house, a private dock, multiple waterfront cottages and a number of full homes—one of which dates to 1850—a 20-stall horse stable made of granite with a tiled arch ceiling, a riding arena, a sand dressage ring and an equestrian exercise track.

The property was formerly a vacation home for baking powder titan William Ziegler and is still owned by his descendants. Ziegler died at the estate in 1905.