San Diego, the state's second-most populous county, had a population of 3,336,081 persons in fiscal year 2025, an increase of 0.32% over 2024's figures, according to data released Friday by the California Department of Finance.
The county's population of 3,325,274 last year increased by 10,807 in 2025, data showed.
Overall, California's population grew by about 19,200, or 0.05%, in the fiscal year, reaching 39,529,000 people, the department found.
The 0.05% increase marks the third year of population growth for the state following two consecutive years of declines during the pandemic.
With the Trump administration's immigration policy, and deaths returning to long-term trends, California is likely to experience slower growth over the coming several years, according to the state finance department.
The state's 10 largest counties — including San Diego, Los Angeles, Orange and Riverside — represent 72% of California's population. Seven of the 10 counties with 1 million or more people had positive population growth, leaving three, including Los Angeles and Orange counties, with population loss.
L.A. County had the largest numeric decline — almost 28,500 people in fiscal year 2025. The decrease was driven by higher domestic migration due to impacts of nine destructive wildfires, especially the Palisades and Eaton fires, and a significant decrease in net international migration, according to the finance department.
Across the state, net international migration reached 126,000 people in the year ending July 1, a significant gain in overall population growth. However, negative net domestic migration still outweighed the gains, resulting in a net total migration loss of over 89,000 residents, the department stated.
