A mansion in Hillsboro Beach, Florida, closed at $42 million, marking the town’s biggest real‑estate transaction in almost ten years. The beachfront property, which spans both the Atlantic Ocean and the Intracoastal Waterway, was listed at $59.95 million in December before a price cut brought the asking price to $54.5 million in February. The deal finalized in mid‑June, according to filing records.
Location and property details
Hillsboro Beach sits in Broward County, a narrow 3.2‑mile stretch of the A1A coastal highway that locals call “Millionaires’ Mile.” The area is known for its luxury waterfront homes, many of which sit on narrow parcels with limited ocean frontage. This estate stands out because it occupies both sides of A1A, offering direct access to the beach on one side and the Intracoastal on the other.
The residence measures 10,100 square feet and includes seven bedrooms. It sits on a 2.35‑acre lot, providing ample space for potential expansion. The home was originally built in 2021 for $20 million, according to public records, and underwent a full‑scale renovation that upgraded finishes throughout.
Buyer and seller information
The seller, who held the property in a trust, was not identified in the transaction documents. The buyer, Mason Slaine, is a former chief executive of Thomson Financial—now part of Thomson Reuters—and serves as vice chair of the Boca Raton Regional Hospital Foundation’s board. He also holds positions at Advent International, a Boston‑based private‑equity firm, and at Minesoft, a patent‑intelligence company.
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“Houses on the beach in South Florida don’t come on the market very much,” Slaine told reporters. “It’s like buying a rare painting—when they come up for sale, if you don’t buy it, you’ll have to wait another five or ten years and pay three times as much, so that’s why I grabbed it.” His agent, Senada Adžem of Douglas Elliman, added that the property offers “unobstructed views from the Atlantic Ocean to the Intracoastal Waterway” and a level of privacy that is increasingly hard to find.
In a brief comparison, this sale resembles the 2018 auction of nearby Playa Vista Isle, which fetched $42.5 million. Both transactions involved a mansion and an adjacent vacant lot, highlighting the premium placed on dual‑waterfront access in the region.
While plans remain tentative, Slaine indicated that he and his wife, Daniele, may add a guest house on the Intracoastal side and later consider a tennis court or a small three‑hole golf course. “On the main land, we’re going to plan a really big party, so we’re not going to do anything in terms of building until after that,” he said.
From a broader perspective, the price point reflects a trend where ultra‑luxury homes in South Florida command high values despite a relatively modest inventory. The scarcity of oceanfront parcels with both beach and Intracoastal frontage pushes buyers toward properties that can accommodate future development, a factor that likely contributed to the willingness to pay a near‑record sum.
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Hillsboro Beach’s proximity to Boca Raton also played a role. Slaine, who is active in local philanthropy, noted that the only beachfront residential options in Boca are condos, and similar offerings in neighboring Delray Beach or Highland Beach did not meet his criteria. “This was the only house that had all the things we wanted,” he said, adding that the ten‑minute drive to his existing residence made the location convenient as well.
It set a new local record.
The transaction closed on Tuesday, finalizing a deal that began with a listing near $60 million and ended at $42 million—a sizable discount but still a landmark figure for the small town. The property’s dual waterfront access, sizable lot, and recent renovations were likely key factors that justified the price in a market where comparable homes are scarce.
