Fastest Growing Counties in California (2025)

County
Rank
Change (2020)
2025 Pop.
2020 Pop.
Yuba County17.93%88,46081,958
Madera County27.4%167,916156,345
San Benito County37.3%69,23964,530
Placer County47.05%434,535405,927
Merced County54.79%295,340281,830
Amador County64.74%42,44740,525
Riverside County74.37%2,528,8442,422,993
San Joaquin County84.32%814,309780,617
Calaveras County92.72%46,58345,348
Colusa County101.96%22,29321,864
Tulare County111.84%482,636473,914
Fresno County121.11%1,020,7681,009,552
San Bernardino County130.62%2,197,0172,183,391
Yolo County140.6%217,596216,291
Kern County150.23%907,958905,910
El Dorado County16-0.09%191,071191,245
Sacramento County17-0.16%1,584,1041,586,566
Imperial County18-0.18%179,291179,612
Stanislaus County19-0.26%551,838553,257
Mono County20-0.26%13,19413,228
San Luis Obispo County21-0.38%280,825281,884
Kings County22-0.51%152,072152,844
Solano County23-0.63%449,884452,723
Nevada County24-0.93%101,309102,265
San Diego County25-1.21%3,255,5673,295,298
Contra Costa County26-1.29%1,151,0371,166,069
Lake County27-1.33%67,29068,199
Shasta County28-1.53%179,224182,002
Butte County29-1.61%206,778210,151
Sonoma County30-1.68%480,098488,282
Sierra County31-2.14%3,1563,225
Ventura County32-2.41%823,028843,371
Tehama County33-2.43%64,09065,687
Orange County34-2.49%3,106,5213,185,734
Monterey County35-2.72%426,401438,322
Mariposa County36-2.73%16,65117,119
Santa Barbara County37-2.78%435,941448,424
Sutter County38-2.79%96,70699,479
Santa Clara County39-2.85%1,876,1061,931,168
Humboldt County40-3.08%132,067136,262
Tuolumne County41-3.5%53,43855,379
Trinity County42-3.96%15,45416,091
Marin County43-3.98%250,913261,306
Alameda County44-4.19%1,610,0461,680,466
Glenn County45-4.28%27,66728,904
Los Angeles County46-4.43%9,550,5059,992,813
Mendocino County47-4.44%87,31091,367
Inyo County48-4.69%18,09718,987
Napa County49-4.77%130,908137,459
Modoc County50-4.83%8,2628,681
Santa Cruz County51-5.29%256,161270,474
San Mateo County52-5.41%721,201762,479
Plumas County53-6.27%18,50719,746
Siskiyou County54-6.48%41,14343,995
San Francisco County55-6.79%811,416870,518
Del Norte County56-7.47%25,54327,604
Alpine County57-13.44%1,0431,205
Lassen County58-17.86%26,54332,315

California County Growth Overview

California's counties show varied growth patterns from 2020 to 2025. Yuba County leads with 7.93% annualized growth, followed by Madera County (7.4%) and San Benito County (7.3%). The largest counties are Los Angeles County (9,550,505), San Diego County (3,255,567), and Orange County (3,106,521). Of the 58 counties in California, 15 are growing while 43 have experienced population decline. Overall, counties averaged -1.61% annualized growth, with total population growing by -1.74% annually.