Atherton ZIP Code Is Still Nation's Priciest In 2023

ATHERTON, CA — More than three dozen Bay Area ZIP codes were among the most expensive in the country this year, despite declines in median sale prices in many areas this year. Atherton retained its title as home to the nation's most exclusive ZIP code as prices soared even higher.

To determine the nation's 100 most expensive ZIP codes, real estate data firm PropertyShark considered all home transactions that closed between early January and late October.

PropertyShark said it "calculated median sale prices based on closed home sales, not asking prices, as we consider this methodology to provide the most accurate picture of actual market dynamics. Whereas asking prices reflect sellers' wishes, calculating medians based on sale prices reflects the transactional reality on the ground."

California claimed 79 of the most expensive ZIP codes in the country — the most of any state. Despite nine ZIP codes dropping off the list this year, the Bay Area accounted for nearly half of that total.

Atherton's 94027 ZIP code kept its long-running crown as the nation's costliest, where the median sale price ballooned to $8.3 million this year. The 5.5 percent increase kept the exclusive enclave comfortably in first place and at nearly twice the price of the city in 10th place.

Marin County also landed in the top 10, where Stinson Beach's 94970 ZIP code tied for sixth place with a $4.5 million median sale price —a 27 percent leap from the year before.

By contrast, more than half of the nation's most expensive ZIP codes saw price declines in 2023, led by Marin County's 94957 ZIP code in Ross where they plummeted by a nation-leading 39 percent, falling from third place last year to 21st this year. Researchers pointed to a notable decrease in the square footage of the homes that changed hands this year as a potential factor.

According to PropertyShark, Santa Clara County had the highest concentration of Bay Area ZIP codes in the top 100, logging 16 spots on the list. San Mateo County nabbed eight spots, followed by Marin County with six, Contra Costa County with four, and San Francisco with three. Alameda County dropped out of the top 100 after claiming three ZIP codes last year.

Here are the San Mateo County ZIP codes that ranked among the 100 priciest for homes in 2023:

• #1: Atherton - 94027 - $8.3 million
• #15: Portola Valley - 94028 - $3.8 million
• #22: Hillsborough/Burlingame - 94010 - $3.2 million
• #38: Menlo Park - 94025 - $2.7 million
• #47: Redwood City - 94062 - $2.45 million
• #62: San Mateo - 94402 - $2.2 million
• #79*: Belmont - 94002 - $2 million
• #79*: San Carlos - 94070 - $2 million

>> The full "100 Most Expensive U.S. Zip Codes in 2023" report can be found here.