California's fastest growing counties are in the state's inland areas, while some of its biggest metro areas are seeing the biggest population decreases, per an Axios analysis of the latest census data.
Why it matters: The zoomed-in analysis offers a closer look at population change within states.
Driving the news: San Diego County's population shrunk by 20,051 people from 2014-2018 to 2019-2023, or a change of 0.6%.
Los Angeles County's population decreased by 2.5% and San Francisco County's fell by 3.9% during that same time.
Sacramento County grew by 4.9% during that period, while Riverside County led Southern California with its 2.8% growth rate.
Zoom in: San Diego's natural population change — the difference between births and deaths — was positive in 2023.
But more people moved away than moved here during that time, so the region's overall population shrunk.
Between the lines: At the national level, international immigration is the primary driver of population change, with migration accounting for 84% of the country's growth between 2023 and 2024.