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One of the most distinguished teams on the DC scene. Throughout their combined 40+ year career and
1.5 billion dollars sold, the McFadden name has become synonymous with expertise and superior results, best-in-class service, and an unyielding dedication to his clients.
Thanks to Mark’s and Hunter’s unrivaled work ethic, negotiating prowess, and vast market knowledge, he has earned the trust of buyers and sellers alike throughout the greater DC region.
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Latest News
Massive Georgetown mansion Halcyon House has traded hands to a residential buyer after the namesake nonprofit startup accelerator it housed for more than a decade completed its move to another part of D.C. this week.
Prospect Street NW LLC — the identity of which was not immediately clear — has acquired the more than 30,000-square-foot property at 3406 Prospect St. NW for $28 million 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. Ueno’s holdings in the affiliate remain unclear following his divorce from Kuno.
The property’s 2025 assessed value is $15 million. Kuno was represented by Compass’ Mark and Hunter McFadden. TTR Sotheby’s represented the buyer.
The house served as the home to business development group Halcyon, which Kuno and Kate Goodall founded as an incubator in 2014 before turning it into a nonprofit in 2017. Goodall served as its CEO until 2024, when she launched Halcyon Venture Partners as a spinoff investment arm.
On Monday, Halcyon completed its relocation to a smaller WeWork space at 1100 15th St. NW, which a spokesperson previously said would allow Halcyon to better serve startups in more cities.
“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 us in an email. “I’m also proud to continue to support Halcyon Accelerator in their new home in downtown D.C.”
Halycon first announced it would vacate its namesake mansion in July as part of Kuno’s “succession planning vision,” the details of which have not been fully unveiled.
The move also coincided with a planned change in strategy for Halcyon, which is expanding the focus of its business support and development resources to better accommodate emerging companies globally instead of focusing on those that can locate to D.C. for multimonth, in-person residencies.
The Halcyon House was built in 1787 by the first U.S. secretary of the Navy, Benjamin Stoddert. It is located in the heart of Georgetown, and at one point was owned and expanded by Mark Twain’s nephew, Albert Clemens.
Word of the final sale of Halcyon House comes the same day Goodall posted on LinkedIn that she is joining forces with Kuno again on a project that involves Kuno’s S&R Evermay Foundation, the renamed S&R Foundation. The project is called Embassy of the Future.
“We will host fellows and events all focused on our world a decade from now, with the goal of connecting wisdom to the profound opportunities before us,” Goodall wrote.
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Featured Property
9112/9120 MINE RUN DRIVE
Great falls
$14,000,000 | 8 BD | 10 BA | 2 HB |
Nestled on 5.44 acres near Great Falls Park, this estate blends old-world craftsmanship with modern luxury. A gated drive leads to the stately Manor, featuring Swarovski crystal chandeliers throughout. The property also offers a charming Guest Cottage, expansive wine cellar, elegant gardens, fountains, and timeless architectural details.
Mark McFadden | Hunter McFadden
mark.mcfadden@compass.com | 703.216.1333
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