County Maps US

San Luis Obispo County, California

A county in California, ranked 24 of 58 by population.

CountyFIPS 06079

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

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Population
282,367
+110 (0%) since 2020
Land area
3,301
square miles. A further 8.7% of the total area is water
Population density
85.5
people per square mile, computed rather than published
County seat
San Luis Obispo
Seat of county government.
Established
1850
175 years ago
Largest city
San Luis Obispo city
Population 50,636.

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 San Luis Obispo 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 San Luis Obispo 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 505 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 San Luis Obispo 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
Population282,36724th of 58260th of 3,144
Land area3,301 sq mi16th of 58153rd of 3,144
Population density85.5 per sq mi34th of 581,032nd of 3,144
Median household income$97,44620th of 58193rd of 3,143

Full data for San Luis Obispo County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population282,367Vintage 2025 Population Estimates
Population in 2020282,257Vintage 2025 Population Estimates
2020 estimates base?282,440Vintage 2025 Population Estimates
Land area3,301 sq mi2025 Gazetteer Files
Water area314.9 sq mi2025 Gazetteer Files
Total area3,616 sq mi2025 Gazetteer Files
Population density?85.5 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$97,446American Community Survey 2020-2024 5-Year Estimates
Median home value$824,700American Community Survey 2020-2024 5-Year Estimates
Median age40.4American Community Survey 2020-2024 5-Year Estimates
Households109,503American Community Survey 2020-2024 5-Year Estimates
Housing units125,669American 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
-164
2,452 births, 2,616 deaths
Net migration
+367
More people moved in than moved out.

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

The 4 areas bordering San Luis Obispo 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
Santa Barbara CountyCalifornia109 mi442,065
Kern CountyCalifornia103 mi927,068
Monterey CountyCalifornia69 mi433,729
Kings CountyCalifornia1.1 mi154,327

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.