In the late 1940s, landscaper Robert Royston joined with office mate and architect Joseph Allen Stein to develop a couple of neighboring Bay Area homes for their families on a hillside parcel overlooking Mill Valley and Mount Tamalpais, just north of the Golden Gate Bridge.

Surrounding the Usonian-inspired structures are gardens and patios that served as a living lab for Royston’s modernist design principles for more than six decades, replete with an eye-catching screen wall featuring abstract concrete and metal panels by artist Florence Swift that was displayed at the San Francisco Museum of Modern Art’s 1949 Design in the Patio exhibition.

“I looked over his shoulder at a house he was designing for himself, and I liked it,” recalled Royston. “So I bought half his property and did a reverse plan in exchange for doing his garden. It was a good deal.”

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Though Stein decamped his home for India in the 1950s to head the architecture department at Bengal Engineering College, Royston lived on his portion of the property until he passed away in 2008 at age 90. Lovingly maintained and owned by the same family ever since, his personal residence has now hit the market for the first time with a nearly $3 million price tag. Renee Adelmann of Bay Area Modern Residential Real Estate holds the listing.

Set on three-quarters of an acre, the single-level, flat-roofed digs offer four bedrooms and two bathrooms in roughly 2,200 square feet. A triangular, skylight-topped living area serves as a centerpiece, showcasing poured concrete floors, wood paneling, built-in furnishings, a wood-burning fireplace beneath a corrugated copper wall, and glass doors spilling out to a patio lined with the aforementioned architectural screen.

Other highlights include a spacious dining room, a kitchen sporting a vintage Wolf range and a breakfast bar, and a laundry room that doubles as an office with a built-in desk and shelving. Two bedrooms and a bathroom sit beyond the kitchen, while a primary suite secluded on the opposite side of the house has a large dual-sided closet, a vanity station, a bathroom with a walk-in shower, and an adjoining sitting room with a hidden recessed cocktail bar.

Rounding it all off in style are the Royston-designed grounds, which host a series of outdoor vignettes ideal for al fresco lounging and entertaining. There is also an elevated view deck, which sits atop a separate 352-square-foot cantilevered space with a fireplace and a powder room that served as Royston’s design studio, plus a detached carport with room for two vehicles.

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By the time Royston retired from full-time practice in the 1990s, per Dwell, his firm’s projects included nine national and state parks, 10 regional and county parks, 109 city and community parks, numerous residential gardens, and communities such as Sunriver, Oregon.

He also earned many professional accolades, including Fellow of the American Society of Landscape Architects, the American Institute of Architects Medal, and the American Society of Landscape Architects Medal, the professional organization’s highest honor.

Click here for more photos of the Mill Valley residence.