Alameda County, California

County seat: Oakland · Population 1.6 million (2025) · 738 sq mi

Alameda County is the 7th most populous of California's 58 counties, with 1,636,630 people (2025 estimate). Its county seat is Oakland. The map shows its 14 cities and towns and the 6 neighboring counties.

Map of Alameda County, California with cities, towns and the county boundary
Alameda County, California with its cities and towns, unincorporated communities (CDPs) and neighboring counties. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
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Alameda County facts

County seat
Oakland
Population (2025 estimate)
1,636,630 −2.7% since 2020
Land area
738 sq mi 50th largest of 58
Water area
84 sq mi
Population density
2,219 per sq mi
Established
1853
Named after
Rancho Arroyo de la Alameda Mexican land grant in California
Largest city
Oakland 440,838
Median household income
$129,367
Cities and towns
14 plus 6 CDPs
ZIP codes
53
Time zone
Pacific
FIPS code
06001

Cities and towns in Alameda County

Alameda County has 14 incorporated cities, towns and villages. Populations count the people living inside Alameda County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
Oakland (county seat)City440,838
FremontCity226,442
HaywardCity157,113
BerkeleyCity121,911
San LeandroCity85,353
LivermoreCity83,457
AlamedaCity76,876
PleasantonCity74,556
DublinCity71,602
Union CityCity65,282
NewarkCity47,895
AlbanyCity19,195
EmeryvilleCity13,251
PiedmontCity10,642

Unincorporated communities (CDPs)

Census-designated places are communities without their own city government; the county provides their services.

CommunityPopulationAlso in
Castro Valley65,001
San Lorenzo29,171
Ashland22,210
Cherryland14,143
Fairview10,745
Sunol847

ZIP codes in Alameda County

53 ZIP codes reach into Alameda County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of Alameda County, 2020–2025

Alameda County shrank by 45,616 people (−2.7%) between April 2020 and July 2025: 29,794 more births than deaths and a net loss of 74,335 people from migration.

Year (July 1)Population
20201,680,489
20211,644,275
20221,633,138
20231,633,055
20241,636,624
20251,636,630

Neighboring counties

Printable Alameda County map

The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.

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Sources

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