California is home to America’s most expensive zip code — where homes cost over $10M

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Atherton is back on top, and this time it made history. That is, ultra-wealthy history.

The teeny-tiny Silicon Valley enclave beloved by tech bros and wealthy professionals in fleece vests reclaimed the No. 1 spot on PropertyShark’s annual ranking of the priciest ZIP codes in the US.

Atherton’s 94027 ZIP code posted a median home sale price of $10.75 million through the first nine months of 2026, according to the ranking. It represents the first ever ZIP code in the United States to clear the $10 million median threshold.

Prior to Tuesday’s ranking results, Fisher Island in Miami Beach had been king of the gold-dipped hill, but has since slipped to third, with a median of about $7.21 million, behind second-place Sagaponack in the Hamptons, New York.

The Bay Area’s Atherton has now held the top ranking in nine of the past 11 years.

Located in San Mateo County and just a stone’s throw from Stanford and Meta headquarters in Palo Alto, the posh town of fewer than 7,000 residents is a favorite of tech founders, venture capitalists and the nouveau riche AI crowd.

Atherton is a purely residential sanctuary with strict one-acre minimum single-family lot sizes and zero commercial zoning. It leans rural, with no commercial restaurants, downtown shopping streets or retail stores.

That unique combo of scarcity, privacy and proximity to Silicon Valley’s business and tech hubs has long made Atherton a magnet for eight- and nine-figure deals.

The real estate boom is mostly being fueled by AI wealth. Stock windfalls from companies like OpenAI, Anthropic and SpaceX have sent newly minted millionaires and cashed-up billionaires hunting for trophy estates close to Silicon Valley’s epicenter, and further afield to San Francisco.

Notable Atherton residents have included billionaire tech investor Marc Andreessen, WhatsApp co-founder Jan Koum and Golden State Warriors’ Stephen Curry.

Indeed, several real estate sales above $30 million have already closed in 2026.

California still dominates the overall list of the 100 most expensive ZIP codes, though its slice of the pie has slightly thinned since the COVID pandemic as wealth has spread to New York, Florida and other coastal retreats and mountain pockets.

“The demand is among the strongest I have seen in my career,” luxury realtor Ken DeLeon told Bloomberg earlier this year.

Even so, the Golden State’s signature ultra-luxury market just set a new national benchmark.

In Atherton, the price of entry for a typical home is now more than $10 million — and rising.

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