A formal application has landed at San Mateo City Hall for a sprawling housing complex that would finally wipe the closed Hillsdale Inn off the map, along with a self-car wash and car-rental lot next door. The proposal calls for 278 homes across a three-acre site at 477 and 341 East Hillsdale Boulevard, marking the furthest this long-dormant parcel has gotten toward redevelopment in over a decade.
The project comes from developer SummerHill Apartment Communities, which is pursuing the development under the state's Housing Crisis Act, also known as SB 330 — a law that, according to the City of San Mateo, locks in the development standards, fees and regulations in place when an application is submitted, so long as the required preliminary paperwork was filed. City materials describe the plan as a seven-story multifamily and townhome development that would replace the closed, 58,955-square-foot Hillsdale Inn. San Francisco YIMBY's February 11, 2026 report describes the project as including 276 dwelling units, including 247 apartments and 28 townhouse-style condominiums, across approximately 462,750 square feet. The city lists 278 total dwelling units, including 30 urban one-bedroom, 147 one-bedroom, 54 two-bedroom and 18 three-bedroom apartments.
Townhomes, Amenities and a Dense Unit Mix
Alongside the apartment tower, the plan calls for a townhouse component of 29 for-sale units spread across five buildings, offering three- and four-bedroom layouts, per the city's community meeting transcript. The apartment building itself is expected to include a mix of amenities — a lobby, lounge, fitness area, pool and spa, rooftop deck and landscaped courtyards, according to the city.
Affordability is also part of the pitch. The project is slated to include 41 below-market-rate units, with 37 deed-restricted for very low-income households and four reserved for moderate-income households, the February filing on San Francisco YIMBY states. Parking and bike-storage figures have likewise varied between documents: earlier project materials described capacity for 350 cars and 314 bicycles, while the city lists 292 parking spaces for the seven-story building.
Design Team and a Site Near Park Place
TCA Architects is overseeing the apartment building's design, while SDG Architects is handling the townhouse architecture, SummerHill's February filing noted. The site sits near Kaiser medical offices, a police station and the Park Place shopping and office complex — a development originally built by Spieker Properties and Equity Office that today includes more than 500 apartments, office space, a grocery store and several shops.
The application invokes state density bonus law. The site's Residential Medium 2 zoning permits four to six stories and 51 to 99 dwelling units per acre — up to 303 units before any density bonus is applied, according to the transcript. The project is expected to seek a statutory exemption from environmental review under Assembly Bill 130.
A Thirteen-Year Saga of Redevelopment Plans
This isn't the first attempt to redevelop the Hillsdale Inn parcel. It is, in fact, the fourth housing proposal for the site since 2013 — and by a wide margin the largest, according to Houseberry. Earlier iterations included a four-story, 230-unit building floated in 2016, a formal application filed in 2020, and another SB 330 version in 2022, but the city confirms that prior version of the project was withdrawn in May 2024.
Part of a Bigger Post-Measure T Building Boom
The Hillsdale Inn site is one piece of a much larger wave of housing proposals moving through San Mateo. By April 2025, roughly 3,000 apartment units had been proposed citywide since Measure T passed, Houseberry reports, and the city continues to push forward what the San Mateo Daily Journal describes as a robust development pipeline, particularly in dense residential and commercial corridors. The Planning Commission recently approved a separate six-story, 181-unit apartment building on North San Mateo Drive that includes 19 below-market-rate units, the paper reported.
The broader housing push has also touched San Mateo County's approach to converting existing buildings. A civil grand jury reviewing the county's Homekey program found in June 2024 that officials had converted five hotels into 315 housing units at a cost about 43 percent below new construction, per Houseberry's reporting. Whether the Hillsdale Inn site ultimately becomes new construction on the scale SummerHill has proposed will depend on hearings still more than a year away.
