County Maps US

Mendocino County, California

A county in California, ranked 39 of 58 by population.

CountyFIPS 06045

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

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Population
88,122
-3,226 (-3.5%) since 2020
Land area
3,507
square miles. A further 9.6% of the total area is water
Population density
25.1
people per square mile, computed rather than published
County seat
Ukiah
Seat of county government.
Established
1850
175 years ago
Largest city
Ukiah city
Population 16,068.

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 Mendocino 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 Mendocino 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 619 by 800 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 Mendocino 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
Population88,12239th of 58679th of 3,144
Land area3,507 sq mi15th of 58143rd of 3,144
Population density25.1 per sq mi44th of 582,064th of 3,144
Median household income$68,09244th of 581,333rd of 3,143

Full data for Mendocino County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population88,122Vintage 2025 Population Estimates
Population in 202091,348Vintage 2025 Population Estimates
2020 estimates base?91,585Vintage 2025 Population Estimates
Land area3,507 sq mi2025 Gazetteer Files
Water area371.3 sq mi2025 Gazetteer Files
Total area3,878 sq mi2025 Gazetteer Files
Population density?25.1 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$68,092American Community Survey 2020-2024 5-Year Estimates
Median home value$512,200American Community Survey 2020-2024 5-Year Estimates
Median age44.1American Community Survey 2020-2024 5-Year Estimates
Households34,842American Community Survey 2020-2024 5-Year Estimates
Housing units41,675American 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
-152
746 births, 898 deaths
Net migration
-661
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 Mendocino 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
Lake CountyCalifornia86 mi67,772
Sonoma CountyCalifornia50 mi486,444
Trinity CountyCalifornia34 mi15,720
Humboldt CountyCalifornia31 mi131,647
Glenn CountyCalifornia18 mi28,141
Tehama CountyCalifornia16 mi64,665

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

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.