Oheka Castle

Otto Hermann Kahn was born in Mannheim, Germany, in 1867, the son of a banker, and was nationally prominent in banking from the 1890s until his death. He was also a leading patron of the arts. He became chairman of the Metropolitan Opera Company in 1911 and served as its president from 1918 to 1931. His country house took its name from his own: Otto Hermann Kahn.

The National Register nomination says three architectural firms competed for the commission and that Delano & Aldrich won with a design that deliberately recalled Clarence Mackay's French-style Harbor Hill in nearby Roslyn. To give his house a commanding site, Kahn had it built on an artificial hill. The official site dates the start of construction to 1914 and completion to 1917; the nomination gives the building period as 1915 to 1917 and notes that the First World War briefly halted work on the house and grounds. As first built, the house had 127 rooms covering about 109,000 square feet by the official site's count, or an estimated 110,000 square feet in the nomination, which calls it the largest house Delano & Aldrich ever designed. The exterior is stucco with limestone trim under a steep slate roof. The estate covered 443 acres, with an 18-hole golf course, terraced lawns, and formal gardens. The Olmsted Brothers worked on the water gardens near the house for about a year from 1917, and Beatrix Farrand resumed garden work in 1919. Farrand's gardens did not survive.

Kahn died of a heart attack in 1934. The nomination says the estate was then sold to the City of New York and used by the Department of Sanitation as a retreat for its workers until the Second World War; the official site says a sanitation workers' welfare fund bought it in 1936 and that a merchant marine radio school used it in 1939. The Eastern Military Academy occupied the house from 1948 to 1978. After that school's bankruptcy the mansion stood empty and was vandalized. Most of the land was subdivided, and the golf course passed to separate ownership.

The developer Gary Melius acquired the house in 1983 or 1984 (both years appear in the sources), when about 22 or 23 acres remained. He began a restoration that the official site puts at $40 million, and in 1996 a Terrace Room addition brought the house to about 115,000 square feet. Oheka was listed on the National Register of Historic Places in 2004. It operates as a hotel with 34 guest rooms and suites, a restaurant, and a wedding and event venue, and docent-led tours run by reservation. The owning entity, Kahn Property Owner LLC, filed for Chapter 11 protection on July 31, 2025, and a court-approved auction is scheduled for October 27, 2026; the buyer must honor events already booked through March 31, 2028.