Atherton (/ˈæθərtən/ ATH-ər-tən) is an incorporated town in San Mateo County, California, United States.

[9] Atherton is known for its high concentration of wealth; in 1990 and 2019,[10] Atherton was ranked as having the highest per capita income among U.S. places that have a population between 2,500 and 9,999,[11] and the area covered by its ZIP Code is regularly ranked as having the highest cost of living in the United States.

In 1923, it was decided to rename the town in honor of Faxon Dean Atherton, a former 19th century landowner on the south peninsula.

[17] The town has been involved in lawsuits to block or delay the introduction of California High-Speed Rail.

[18][19] Atherton was an early and vocal opponent of the electrification of the U.S. commuter railroad Caltrain, which serves cities in the San Francisco Peninsula and Silicon Valley.

Residents opposed electrification and the proposed high-speed rail route because the overhead electrical lines would require tree removal and the town could potentially be divided by the closing of the two grade crossings at Fair Oaks Lane and Watkins Avenue.

[21] In July 2015, the suit proceeded after Caltrain's request to the Surface Transportation Board to exempt it from California Environmental Quality Act (CEQA) guidelines was denied.

Atherton reiterated its opposition to electrification on the basis that overhead wires would require removing a significant number of heritage trees, and city representatives asserted that "newer, cleaner, more efficient diesel trains" should supplant plans for "century-old catenary electrical line technology".

Atherton mayor Rick De Golia was quoted as saying "Caltrain is locked into an old technology and 20th century thinking".

[27] Mullin noted "this entire Caltrain corridor is the epicenter of the innovation economy and it's a job creation and economic engine.

This electrification project, I would argue, is monumental with regard to dealing with [increased traffic and environmental impacts] effectively and efficiently.

[30][11] According to the San Francisco Chronicle, "the town's ascendance stems largely from its single-family zoning, 1-acre-minimum lot sizes, flat land, streamlined permits and changing buyer demographics — which have translated into soaring house sizes and skyrocketing prices.

[9] Partly as a result of these regulations, the average home price in the city in recent years was more than 7.5 million dollars.

[32][37] In 2022, California Governor Gavin Newsom singled out Atherton in a speech for its restrictive housing policies.

[40] As of November 2022, Atherton's stated land-use goal is to "preserve the Town's character as a scenic, rural, thickly wooded residential area with abundant open space.

[47][48] Property Shark ranked Atherton first for the fourth year in a row as the most expensive ZIP code in the United States in 2022, with the median home price at $7,900,000.

There are also several tracts of contemporary Eichler homes, most notably in the Lindenwood neighborhood in the northeast part of the town.

[52] The Holbrook-Palmer Estate was donated to the city of Atherton in 1958 and now serves as a 22-acre public park (8.9 ha) and is listed on the National Register of Historic Places for the architecture.