Fastest Growing Counties in California (2026)

County
Rank
Change (2020) ↓
2026 Pop.
2020 Pop.
Placer County110.82%449,883405,971
San Benito County210.16%71,07964,525
Yuba County39.69%89,94181,996
Madera County48.52%169,722156,396
San Joaquin County56.39%830,481780,618
Riverside County65.62%2,560,7202,424,446
Merced County75.24%297,713282,895
Yolo County83.58%225,560217,760
Calaveras County93.01%46,71445,349
Amador County102.99%41,77840,567
Fresno County112.74%1,037,2141,009,563
Tulare County122.64%486,441473,915
Kern County132.6%929,488905,960
Sacramento County142.54%1,627,0231,586,769
San Bernardino County152.12%2,229,4182,183,200
Kings County161.13%154,535152,813
Stanislaus County170.79%558,066553,702
Solano County180.61%455,676452,895
El Dorado County190.54%192,275191,237
Contra Costa County200.37%1,170,6061,166,249
Imperial County210.29%180,051179,532
San Luis Obispo County220.11%282,581282,257
Shasta County23-0.16%181,904182,191
Butte County24-0.18%209,836210,204
Sonoma County25-0.2%487,525488,514
Santa Clara County26-0.54%1,920,8721,931,349
Nevada County27-0.59%101,676102,280
San Diego County28-0.73%3,276,9543,301,110
Lake County29-0.8%67,66468,208
Sutter County30-0.83%98,64199,463
Colusa County31-0.92%21,65621,858
Mariposa County32-1.41%16,88817,130
Orange County33-1.42%3,140,9873,186,167
Monterey County34-1.47%434,011440,493
Santa Barbara County35-1.62%441,049448,325
Tehama County36-1.82%64,56365,760
Ventura County37-1.84%828,271843,793
San Mateo County38-2.12%746,509762,639
Trinity County39-2.21%15,74316,099
Alameda County40-2.61%1,636,6361,680,489
Glenn County41-3.21%27,96228,889
Napa County42-3.42%132,783137,481
Los Angeles County43-3.56%9,641,0009,996,510
Marin County44-3.69%251,684261,337
Humboldt County45-3.91%130,970136,298
Modoc County46-4.17%8,3178,679
Mendocino County47-4.43%87,30591,348
Sierra County48-4.68%3,0753,226
San Francisco County49-5.02%831,213875,139
Inyo County50-5.13%18,01418,989
Siskiyou County51-5.56%41,53643,983
Santa Cruz County52-5.69%256,287271,758
Tuolumne County53-5.84%52,13555,369
Del Norte County54-6.37%25,86127,619
Mono County55-6.84%12,31813,222
Plumas County56-6.85%18,39319,745
Lassen County57-14.55%27,64132,349
Alpine County58-15.25%1,0001,180

California Counties Growth Overview

California's counties show varied growth patterns from 2020 to 2026. Placer County leads with 1.73% annualized growth, followed by San Benito County (1.63%) and Yuba County (1.55%). The largest counties are Los Angeles County (9,641,000), San Diego County (3,276,954), and Orange County (3,140,987). Of the 58 counties in California, 22 are growing while 36 have experienced population decline. Overall, counties averaged -0.15% annualized growth, with total population growing by -0.08% annually.

Change (2020)

-0.05

-0.025

0

0.025

0.05

0.075