A new estate under construction at 2265 Ralston Avenue in Hillsborough has been listed for $19.5 million by Jenn Gilson of Golden Gate Sotheby’s International Realty. Plans call for a five-bedroom main home, a detached accessory dwelling unit and outdoor amenities on a roughly 22,752-square-foot parcel. The listing is being offered before construction is complete.
Key takeaways
The property’s plans combine a large main residence with additional living space, while several features—including a pool and spa—are planned for the site. Listing details remain subject to verification.
- Asking price: $19.5 million
- Planned main residence: 5,132 square feet, with five bedrooms
- Planned detached ADU: about 800 square feet, with two bedrooms
- Lot: approximately 22,752 square feet
What the plans include
The two-story main home is planned with five full bathrooms, two powder rooms and an attached two-car garage. The detached accessory dwelling unit is designed to include two bedrooms, two bathrooms, a kitchen, laundry, a great room and a separate entrance. A preliminary concept also outlines an approximately 500-square-foot junior ADU, which could provide flexible space for guests, family members or a home office.
Outdoor plans include a future pool and spa, covered patios, stone-paved areas, landscaped gardens, a gated entry and guest parking. The estate is being developed by RG Developments, with interiors by Candace Cavanaugh Interiors. The listing announcement says buyers can follow construction progress; final dimensions and square footage are subject to architectural and field verification.
Listing arrives amid major Hillsborough sales
The listing follows Gilson’s representation of the seller in the reported $70 million sale of Villa de Verano at 3000 Ralston Avenue in August 2026. The 12.5-acre property, which includes a residence designed by architect Andrew Skurman, was described in the announcement as the highest home sale in Hillsborough history.
Gilson also represented the sale of the Bing Crosby Estate for $25 million in June 2025. After its renovation, she was engaged to bring that property back to market in 2026 at an asking price of $28.995 million. These transactions place the new Ralston Avenue listing within a series of high-profile Peninsula estate offerings.
A rare new-build opportunity
Hillsborough is a residential community where large minimum lot sizes and a lack of commercial zoning limit the supply of new estate properties, according to the listing announcement. The Ralston Avenue home is in Lower North Hillsborough, near the Burlingame border. Its pre-completion offering gives prospective buyers an opportunity to consider a newly built property while work is ongoing, rather than purchasing an already completed home.