Halcyon House Sells for $28 Million. But to Whom?
By • January 15, 2026 0 1343
Halcyon House, one of Washington’s most historic mansions at 3400-3410 Prospect St., N.W., has been sold for $28 million to a residential buyer. It is the highest price ever paid for a house in the nation’s capital.
The Washington Business Journal first reported the private sale on Jan. 14: “Prospect Street NW LLC — the identity of which was not immediately clear — has acquired the more than 30,000-square-foot property … from Halcyon Georgetown LLC.”
“The seller is an affiliate of Sucampo Pharmaceuticals Inc., co-founded in 1996 by Dr. Sachiko Kuno and her ex-husband Dr. Ryuji Ueno, which acquired the Georgetown mansion in 2012 for $11 million from Prospect Associates, deed records show.”
Kuno was represented by Mark and Hunter McFadden of Compass Real Estate, and TTR Sotheby’s represented the buyer, according to the Journal. Neither Mark McFadden — who had no comment — nor TTR Sotheby’s could tell The Georgetowner who the new owner is, because of nondisclosure agreements.
Other sources, requesting anonymity, indicated to The Georgetowner that the new owner of Halcyon House has houses in several places and will maintain the 239-year-old building as a private residence. Reportedly, about six very qualified potential buyers or their representatives toured the house before the final purchase.
Halcyon House was used as the headquarters for the Halcyon nonprofit, cofounded by Kuno in 2014, which moved its offices to 15th Street this week.
“I’m grateful to have been a steward of such a special property for 15 years, and for it to have done so much good for entrepreneurs in D.C. and around the world,” Kuno told the Journal in an email. “I’m also proud to continue to support Halcyon Accelerator in their new home in downtown D.C.”
The history of Halcyon House is integral to the founding of Washington, D.C. Changed throughout the decades, the building received its most significant renovation in the latter years of the 20th century.
Purchased by Edmund Dreyfuss and Blake Construction in 1966 from Georgetown University, Halcyon House was owned by the Dreyfuss family and its business concerns for almost 46 years, the longest tenure of any of the property’s deed holders, including its builder and original 1787 occupant, Benjamin Stoddert, the first Secretary of the Navy and friend of George Washington.
Sculptor John Dreyfuss, who led the renovation and reconstruction work during the 1980s and 1990s at the house and its gardens, as well as building a lower studio and hall, received an award from the National Trust for Historic Preservation for his efforts.
Update: The Wall Street Journal reported that the Washington Commanders owner, Josh Harris, has purchased Halcyon House. More to come.
