What are the fastest-growing counties in California?
Placer County is the fastest-growing county in California: its population grew 1.72% a year from 2020 to 2025, to 442,081 residents (Census PEP Vintage 2025). San Benito County (1.67%) and Yuba County (1.58%) follow. California as a whole grew -0.09% a year to 39,355,309 residents.
Data as of 2026-09-23. Population, growth and migration: PEP Vintage 2025 · 2020–2025. Income migration: IRS SOI 2022–2023 (2-yr lag).
Top 10 counties in California by population growth, 2020 to 2025
| Rank | County | Population | Growth (% per year) | Net domestic migration | Net international migration | IRS net AGI migration |
|---|---|---|---|---|---|---|
| 1 | Placer County | 442,081 | 1.72% | +31,019 | +5,622 | +$385.9M |
| 2 | San Benito County | 70,082 | 1.67% | +3,550 | +305 | +$4.2M |
| 3 | Yuba County | 88,691 | 1.58% | +4,022 | +676 | +$34.5M |
| 4 | Madera County | 167,927 | 1.43% | +6,049 | +1,590 | +$48.6M |
| 5 | San Joaquin County | 823,815 | 1.08% | +5,869 | +21,824 | +$256.6M |
| 6 | Merced County | 297,260 | 1.00% | +1,932 | +4,540 | -$49.9M |
| 7 | Riverside County | 2,544,916 | 0.97% | +60,885 | +29,797 | +$396.3M |
| 8 | Amador County | 41,876 | 0.64% | +2,267 | +142 | +$20.3M |
| 9 | Yolo County | 224,410 | 0.60% | -3,665 | +7,663 | -$104.8M |
| 10 | Calaveras County | 46,605 | 0.55% | +2,228 | +102 | +$15.2M |
Where are people moving in California?
Riverside County gained the most people from elsewhere in the United States: net domestic migration of +60,885 from 2020 to 2025 (Census PEP Vintage 2025). The table ranks every California place with 10,000 or more residents by that figure; the IRS column shows net adjusted gross income migration for 2022 to 2023.
| Rank | County | Population | Growth (% per year) | Net domestic migration | Net international migration | IRS net AGI migration |
|---|---|---|---|---|---|---|
| 1 | Riverside County | 2,544,916 | 0.97% | +60,885 | +29,797 | +$396.3M |
| 2 | Placer County | 442,081 | 1.72% | +31,019 | +5,622 | +$385.9M |
| 3 | Madera County | 167,927 | 1.43% | +6,049 | +1,590 | +$48.6M |
| 4 | San Joaquin County | 823,815 | 1.08% | +5,869 | +21,824 | +$256.6M |
| 5 | Yuba County | 88,691 | 1.58% | +4,022 | +676 | +$34.5M |
| 6 | San Benito County | 70,082 | 1.67% | +3,550 | +305 | +$4.2M |
| 7 | Amador County | 41,876 | 0.64% | +2,267 | +142 | +$20.3M |
| 8 | Calaveras County | 46,605 | 0.55% | +2,228 | +102 | +$15.2M |
| 9 | Merced County | 297,260 | 1.00% | +1,932 | +4,540 | -$49.9M |
| 10 | El Dorado County | 192,323 | 0.11% | +1,792 | +1,249 | +$93.7M |
Go past the headline numbers
The interactive Demographics map layer and the full report for a single place are part of paid plans.
Get the Demographics Report for Placer CountyFrequently asked questions
- What are the fastest-growing counties in California?
- By population growth from 2020 to 2025, the fastest are Placer County (1.72% a year), San Benito County (1.67% a year), Yuba County (1.58% a year), Madera County (1.43% a year) and San Joaquin County (1.08% a year) (Census PEP Vintage 2025). Only places with 10,000 or more residents are ranked.
- Where are people moving in California?
- By net domestic migration from 2020 to 2025, the largest gains are Riverside County (+60,885), Placer County (+31,019) and Madera County (+6,049) (Census PEP Vintage 2025).
- How fast is California growing overall?
- California grew -0.09% a year from 2020 to 2025, to 39,355,309 residents, with net migration of -657,044 people (Census PEP Vintage 2025).
- Where does this California data come from, and how current is it?
- Population, growth and migration come from the U.S. Census Bureau Population Estimates Program (PEP Vintage 2025 · 2020–2025). Income migration comes from IRS Statistics of Income (IRS SOI 2022–2023 (2-yr lag)). Counties with fewer than 10,000 residents are not ranked (3 of 58 in California). Data last loaded 2026-09-23.
Data as of 2026-09-23: sources and periods
- Population, growth and migration
- U.S. Census Bureau, Population Estimates Program: PEP Vintage 2025 · 2020–2025. census.gov/programs-surveys/popest
- Income migration (net AGI)
- Internal Revenue Service, Statistics of Income migration data: IRS SOI 2022–2023 (2-yr lag). irs.gov/statistics/soi-tax-stats-migration-data
How to read the table
- Population is the Census July 1 estimate of the latest vintage.
- Growth is the compound annual rate over 2020 to 2025.
- Net domestic and international migration are cumulative people over 2020 to 2025.
- IRS net AGI migration is adjusted gross income that moved in, less what moved out, for 2022 to 2023. A plus sign means a net inflow.
- Places with fewer than 10,000 residents are left out of the rankings.