Fastest Growing Counties in California (2026)

County
Rank
Change (2020) ↓
2026 Pop.
2020 Pop.
Placer County111.41%452,268405,951
Yuba County210.99%91,01782,001
San Benito County39.7%70,79564,533
Madera County48.35%169,492156,434
San Joaquin County57.15%836,506780,676
Merced County66.56%301,518282,963
Riverside County76.52%2,582,7012,424,663
Yolo County85.58%229,915217,768
Amador County94.68%42,48240,584
Sacramento County103.65%1,644,6811,586,727
Kings County113.52%158,177152,797
Tulare County123.21%489,144473,944
Santa Clara County133.11%1,984,7011,924,802
Kern County143.11%934,295906,124
San Bernardino County152.64%2,241,2332,183,526
Imperial County162.38%184,002179,730
Contra Costa County172.34%1,193,4631,166,165
Fresno County182.27%1,032,5771,009,613
Solano County192.27%463,183452,887
Calaveras County202.22%46,35545,350
Stanislaus County211.69%563,074553,710
El Dorado County221.22%193,589191,250
Del Norte County230.97%27,88527,616
Colusa County240.77%22,03621,868
San Diego County250.71%3,324,6173,301,182
Orange County260.5%3,202,1793,186,261
Sonoma County270.18%489,393488,501
Nevada County280.14%102,413102,267
Mariposa County290.11%17,15217,133
Butte County300.03%210,294210,222
Shasta County31-0.08%182,051182,190
San Luis Obispo County32-0.15%281,515281,924
San Mateo County33-0.34%760,145762,727
Santa Barbara County34-0.36%446,458448,083
Ventura County35-0.43%840,139843,808
Alameda County36-0.58%1,670,8961,680,614
Monterey County37-0.69%437,479440,506
Sutter County38-0.76%98,72199,479
Lake County39-1.14%67,42468,200
Glenn County40-1.24%28,53228,889
Marin County41-1.36%257,788261,341
Los Angeles County42-1.89%9,807,8639,996,634
Mendocino County43-2.79%88,81791,362
Trinity County44-3.34%15,55816,095
Inyo County45-3.37%18,35918,999
Tehama County46-3.43%63,43565,690
San Francisco County47-3.49%844,276874,826
Tuolumne County48-3.55%53,43355,397
Modoc County49-3.87%8,3418,677
Santa Cruz County50-4.4%259,820271,768
Napa County51-4.49%131,293137,465
Mono County52-5.04%12,55913,225
Humboldt County53-5.28%129,122136,324
Siskiyou County54-5.43%41,61243,999
Plumas County55-7.59%18,26219,761
Sierra County56-7.74%2,9793,229
Alpine County57-11.37%1,0451,179
Lassen County58-15.39%27,34432,319

California Counties Growth Overview

California's counties show varied growth patterns from 2020 to 2026. Placer County leads with 1.82% annualized growth, followed by Yuba County (1.75%) and San Benito County (1.56%). The largest counties are Los Angeles County (9,807,863), San Diego County (3,324,617), and Orange County (3,202,179). Of the 58 counties in California, 30 are growing while 28 have experienced population decline. Overall, counties averaged 0.01% annualized growth, with total population growing by 0.16% annually.

Change (2020)

-0.05

-0.025

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0.025

0.05

0.075