San Luis Obispo and Santa Barbara Counties See Population Declines

Census data shows drop in residents despite state estimates of slight increases

Published on Mar. 5, 2026

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According to the U.S. Census Bureau, both San Luis Obispo and Santa Barbara counties in California have seen declines in population since the 2020 census, despite state estimates showing slight increases. The population drops are attributed to negative foreign migration and residents moving out of the counties during the COVID-19 lockdowns in 2021, though foreign immigration and domestic migration have started to rebound in more recent years.

Why it matters

The population shifts in these coastal California counties reflect broader demographic trends in the state, with more residents leaving for other parts of the country and international immigration declining after a peak in 2024. These population changes can impact local economies, tax revenues, and the demand for public services.

The details

The 2020 census counted 282,424 residents in San Luis Obispo County and 448,229 in Santa Barbara County. By 2021, those numbers had dropped to 277,911 and 438,097 respectively, due to negative foreign migration and residents moving out of the counties. In more recent years, foreign immigration and domestic migration have started to rebound, leading to slight population increases, but the counties have still not returned to their 2020 census levels.

  • The 2020 census counted 282,424 residents in San Luis Obispo County and 448,229 in Santa Barbara County.
  • By 2021, the populations had dropped to 277,911 in San Luis Obispo County and 438,097 in Santa Barbara County.
  • From July 2024 to July 2025, San Luis Obispo County saw 219 foreign immigrants and 159 domestic migrants, while Santa Barbara County saw 644 foreign immigrants and 1,894 domestic migrants.

The players

U.S. Census Bureau

The federal agency responsible for conducting the decennial census and providing population estimates.

State of California

The state government agency that also provides population estimates for California counties.

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What they’re saying

“Even with the higher state generated population counts, both San Luis Obispo and Santa Barbara counties have lost residents since the 2020 census.”

— KAREN VELIE, Author (CalCoastNews)

What’s next

The U.S. Census Bureau projects international immigration to the United States will decline to approximately 321,000 people in 2026, which could further impact population trends in San Luis Obispo and Santa Barbara counties.

The takeaway

The population declines in these coastal California counties reflect broader demographic shifts, with fewer residents moving in from other countries and some existing residents leaving for other parts of the state or country. These changes can have significant economic and social impacts on local communities.