California's Wealthiest Counties Revealed, LA Not in Top 10

Silicon Valley dominates the list, with San Mateo and Santa Clara counties topping the rankings.

Apr. 10, 2026 at 6:24pm

A minimalist, abstract illustration using bold shapes and a muted color palette to represent the uneven distribution of wealth across different regions of California.The stark geographic divide in California's wealth is illustrated through a minimalist, geometric composition.Hillsborough Today

A new study by SmartAsset has revealed the wealthiest counties in California, and the results may surprise some. The top spots are dominated by Northern California counties, with San Mateo and Santa Clara taking the top two positions. In fact, four of the 10 wealthiest counties in the entire U.S. are located in Northern California. The rankings are based on factors like median income, investment income, and home values, with sky-high real estate prices in Silicon Valley bedroom communities like Hillsborough and Atherton driving up the overall 'wealth index' for these areas.

Why it matters

The findings highlight the growing wealth divide in California, with the state's most affluent residents concentrated in the tech-heavy regions of Northern California. This has significant implications for housing affordability, income inequality, and the state's overall economic landscape. The lack of Los Angeles County in the top 10 also challenges the perception of Southern California as the state's wealthiest region.

The details

According to the study, San Mateo County has the highest 'wealth index' in California, driven by a median home value of $1.54 million and a median income of $156,000. Santa Clara County, home to many tech titans, is close behind with a median home value of $1.5 million and a median income of $159,000. Other top counties include Marin, San Francisco, Alameda, and Santa Barbara. On a national level, four of the top 10 wealthiest counties are located in Northern California.

  • The study was published on April 10, 2026.

The players

SmartAsset

A financial technology company that provides personal finance advice and tools.

Hillsborough, California

An exclusive Silicon Valley bedroom community known for its high-end real estate and wealthy residents.

Atherton, California

Another affluent Silicon Valley town that is home to many tech executives and venture capitalists.

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The takeaway

The findings from this study highlight the growing wealth divide in California, with the state's most affluent residents concentrated in the tech-heavy regions of Northern California. This has significant implications for housing affordability, income inequality, and the state's overall economic landscape. The lack of Los Angeles County in the top 10 also challenges the perception of Southern California as the state's wealthiest region.