San Diego County, California

County seat: San Diego · Population 3.3 million (2025) · 4,211 sq mi

San Diego County is the 2nd most populous of California's 58 counties, with 3,282,248 people (2025 estimate). Its county seat is San Diego. The map shows its 18 cities and towns and the 3 neighboring counties.

Map of San Diego County, California with cities, towns and the county boundary
San Diego 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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San Diego County facts

County seat
San Diego
Population (2025 estimate)
3,282,248 −0.5% since 2020
Land area
4,211 sq mi 9th largest of 58
Water area
315 sq mi
Population density
780 per sq mi
Established
1850
Named after
San Diego seat of San Diego County, California, United States; second-largest city in California
Largest city
San Diego 1,406,106
Median household income
$106,268
Cities and towns
18 plus 39 CDPs
ZIP codes
116
Time zone
Pacific
FIPS code
06073

Cities and towns in San Diego County

San Diego County has 18 incorporated cities, towns and villages. Populations count the people living inside San Diego County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
San Diego (county seat)City1,406,106
Chula VistaCity275,533
OceansideCity170,483
EscondidoCity146,030
CarlsbadCity112,260
El CajonCity101,755
VistaCity98,274
San MarcosCity94,908
EncinitasCity60,736
La MesaCity59,914
SanteeCity58,205
National CityCity57,807
PowayCity49,180
Lemon GroveCity27,936
Imperial BeachCity25,206
CoronadoCity21,094
Solana BeachCity12,602
Del MarCity3,858

Unincorporated communities (CDPs)

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

CommunityPopulationAlso in
La Presa34,962
Fallbrook32,112
Spring Valley31,969
Ramona22,634
Lakeside22,447
Winter Gardens22,131
Rancho San Diego21,272
Casa de Oro-Mount Helix19,765
Bostonia16,765
Camp Pendleton South15,766
Alpine15,180
Bonita12,652
Valley Center11,119
San Diego Country Estates10,223
Camp Pendleton Mainside9,501
Jamul6,574
Eucalyptus Hills5,840
Lake San Marcos4,693
Bonsall4,332
Harbison Canyon4,328
Granite Hills3,795
Hidden Meadows3,524
Crest2,775
Campo2,729
Fairbanks Ranch2,703
Borrego Springs2,700
Harmony Grove2,585
Rancho Santa Fe2,260
Rainbow2,029
Pine Valley1,786
Julian1,751
Descanso1,590
Pala914
Boulevard752
Jacumba740
Elfin Forest592
Potrero417
Del Dios379
Mount Laguna93

ZIP codes in San Diego County

116 ZIP codes reach into San Diego County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of San Diego County, 2020–2025

San Diego County shrank by 16,400 people (−0.5%) between April 2020 and July 2025: 62,921 more births than deaths and a net loss of 77,354 people from migration.

Year (July 1)Population
20203,301,110
20213,272,601
20223,279,089
20233,279,736
20243,287,542
20253,282,248

Neighboring counties

Printable San Diego 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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