Rear of Killenworth around 1915, showing the swimming pool
General information
Architectural styleTudor revival
Town or cityGlen Cove, New York
CountryUnited States
Coordinates40°53′01″N 73°38′05″W / 40.8836°N 73.6346°W / 40.8836; -73.6346
Current tenantsRussia
Design and construction
Other designersTrowbridge and Ackerman

Killenworth is a historic mansion in Glen Cove, New York constructed for George Dupont Pratt in 1912. It was purchased by the Soviet Union in 1946 to become the country retreat of the Soviet, and later Russian, delegation to the United Nations. In the 1980s the property was subject to allegations it was being used for espionage. There has been a long-standing conflict with the City of Glen Cove over its tax status.



A portion of Killenworth's gardens, considered James L. Greenleaf's greatest accomplishment

Killenworth was constructed in 1912 as the home of George Dupont Pratt. The building was designed by Trowbridge and Ackerman in the Tudor Revival style with a seam-faced granite facade and had 39 rooms. It won first prize in that year's American Institute of Architects competition for best country house.[1][2] The estate's gardens were designed by James Leal Greenleaf,[3] and were considered his greatest achievement.[4] The current building replaced an earlier mansion, also called Killenworth, which was constructed for Pratt around 1897 by William Tubby, with landscaping by the Olmsted Brothers.[5]

Killenworth is one of five existing mansions in Glen Cove built for the sons of oil magnate Charles Pratt. The others are "The Braes", now the Webb Institute of Naval Architecture; "Welwyn", now the Holocaust Memorial and Tolerance Center of Nassau County on the grounds of the Welwyn Preserve; "Poplar Hill", now the Glengariff Healthcare Center; and "The Manor", now the Glen Cove Mansion Hotel and Conference Center.[6] Their property totaled nearly 5,000 acres.

Diplomatic retreat

In 1946, the estate was purchased by the Soviet Union and used as the country retreat of its delegation to the United Nations.[7][8]

The presence of the Russians made the property the target of demonstrations, requiring the City of Glen Cove to provide additional police protection that was not reimbursed.[7] When Soviet leader Nikita Khrushchev visited Killenworth in 1960, crowds reportedly threw tomatoes at his party's limousines. Other residents simply watched the procession in silence.[9] Cuban leader Fidel Castro also visited Killenworth in Glen Cove while in the United States.[10]

The tax-exempt status of the property led to conflict with the City of Glen Cove, which in 1970 attempted to foreclose on the property until the United States Department of State got a restraining order in federal court to stop the proceedings.[7][11] In the 1980s the facility was subject to allegations that it was being used for espionage, with defector Arkady Shevchenko stating that its top floors were occupied by equipment for signals intelligence.[7][12] In response to this and the tax dispute, in 1982 the city council voted to revoke the Russians' ability to get permits for city beach, golf, and tennis facilities.[7] The Soviet Union retaliated by denying use of a Moscow beach to members of the Embassy of the United States in Moscow. The permit revocation was reversed in 1984.[13]

In December 2016, the Obama administration announced that two Russian diplomatic facilities, one of which was on Long Island, would be closed as part of the retaliation for the Russian interference in the 2016 United States presidential election. It was initially reported that Killenworth might be the Long Island site,[14] but the designated facility turned out to be another mansion owned by the Russians called Norwich House[15] in nearby Upper Brookville, New York.[9][16] Killenworth is still used by the Russian delegation.


  1. ^ Killenworth. Previews Incorporated. Retrieved December 29, 2016 – via Old Long Island.
  2. ^ Moses, Lionel (August 1, 1917). "Killenworth," Residence of Mr. George D. Pratt at Glen Cove, L. I. The Art World.
  3. ^ "James L. Greenleaf". The Cultural Landscape Foundation. Retrieved December 29, 2016.
  4. ^ "James Greenleaf Dies at Age of 75", The New York Times. April 16, 1933.
  5. ^ L., Zach (December 12, 2011). "Killenworth". Old Long Island. Retrieved December 30, 2016.
  6. ^ "The History of The Pratt Family Home on Poplar Hill in Long Island". Glengariff Healthcare Center. Retrieved December 30, 2016.
  7. ^ a b c d e McQuiston, John T. (August 8, 1982). "Russians Long a Thorny Issue". The New York Times. ISSN 0362-4331. Retrieved December 30, 2016.
  8. ^ Durso, Joseph (August 30, 1998). "Chronicling Splendor And Its Dissolution". The New York Times. ISSN 0362-4331. Retrieved December 29, 2016.
  9. ^ a b Olson, David (December 30, 2016). "Russian estate in Upper Brookville vacated". Newsday. Retrieved December 31, 2016.
  10. ^ "This is the Long Island house the US is letting the Russians keep". TheWorld. December 30, 2016. Retrieved February 27, 2022.
  11. ^ United States v. City of Glen Cove, 322 F.Supp. 149 (E.D.N.Y. 1971).
  12. ^ Weiss, Michael (December 29, 2016). "Obama Targets Putin's Spies Over DNC Hack". The Daily Beast. Retrieved December 29, 2016.
  13. ^ Logeman, Henry G. (April 25, 1984). "Killenworth Soviets can use city facilities again". United Press International. Retrieved December 30, 2016.
  14. ^ Taylor, Adam (December 29, 2016). "The luxurious, 45-acre compound in Maryland being shut down for alleged Russian espionage". The Washington Post. Retrieved December 29, 2016.
  15. ^ Kirby, Jen. "International Intrigue Near Long Island's Gold Coast". Daily Intelligencer. Retrieved January 4, 2017.
  16. ^ Steadman, Otillia; Watkins, Ali (December 29, 2016). "This Is What It Was Like at Two Russian Sites the US Wants Closed". BuzzFeed. Retrieved December 30, 2016.