County Maps US

Alameda County, California

A county in California, ranked 7 of 58 by population.

CountyFIPS 06001

Within California
Alameda County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Oakland, the county seat, located via the 2025 Census Gazetteer.

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Population
1,636,630
-43,859 (-2.6%) since 2020
Land area
737.5
square miles. A further 10.2% of the total area is water
Population density
2,219
people per square mile, computed rather than published
County seat
Oakland
Seat of county government.
Established
1853
172 years ago
Largest city
Oakland city
Population 440,838.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Alameda County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Alameda County, California from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 553 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Alameda County ranks

Position among the 58 counties of California, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn CaliforniaNationally
Population1,636,6307th of 5822nd of 3,144
Land area737.5 sq mi50th of 581,200th of 3,144
Population density2,219 per sq mi4th of 5864th of 3,144
Median household income$129,3675th of 5833rd of 3,143

Full data for Alameda County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population1,636,630Vintage 2025 Population Estimates
Population in 20201,680,489Vintage 2025 Population Estimates
2020 estimates base?1,682,246Vintage 2025 Population Estimates
Land area737.5 sq mi2025 Gazetteer Files
Water area83.7 sq mi2025 Gazetteer Files
Total area821.2 sq mi2025 Gazetteer Files
Population density?2,219 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$129,367American Community Survey 2020-2024 5-Year Estimates
Median home value$1,090,100American Community Survey 2020-2024 5-Year Estimates
Median age39.0American Community Survey 2020-2024 5-Year Estimates
Households598,246American Community Survey 2020-2024 5-Year Estimates
Housing units637,212American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+5,593
16,073 births, 10,480 deaths
Net migration
-5,587
More people moved out than moved in.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Alameda County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Contra Costa CountyCalifornia56 mi1,170,070
Santa Clara CountyCalifornia37 mi1,914,391
San Joaquin CountyCalifornia27 mi823,815
San Mateo CountyCalifornia19 mi743,568
San Francisco CountyCalifornia13 mi826,079
Stanislaus CountyCalifornia253 ft557,719

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

Side by side

All 58 counties of California

Open the interactive California county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.