County Maps US

Fond du Lac County, Wisconsin

A county in Wisconsin, ranked 16 of 72 by population.

CountyFIPS 55039

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

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Population
104,669
+510 (+0.5%) since 2020
Land area
719.6
square miles. A further 6.0% of the total area is water
Population density
145
people per square mile, computed rather than published
County seat
Fond du Lac
Seat of county government.
Established
1836
189 years ago
Largest city
Fond du Lac city
Population 44,541.

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 Fond du Lac 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 Fond du Lac County, Wisconsin 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 624 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 Fond du Lac County ranks

Position among the 72 counties of Wisconsin, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn WisconsinNationally
Population104,66916th of 72602nd of 3,144
Land area719.6 sq mi40th of 721,247th of 3,144
Population density145 per sq mi18th of 72715th of 3,144
Median household income$74,27534th of 72888th of 3,143

Full data for Fond du Lac County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population104,669Vintage 2025 Population Estimates
Population in 2020104,159Vintage 2025 Population Estimates
2020 estimates base?104,165Vintage 2025 Population Estimates
Land area719.6 sq mi2025 Gazetteer Files
Water area46.3 sq mi2025 Gazetteer Files
Total area765.8 sq mi2025 Gazetteer Files
Population density?145 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$74,275American Community Survey 2020-2024 5-Year Estimates
Median home value$222,800American Community Survey 2020-2024 5-Year Estimates
Median age41.9American Community Survey 2020-2024 5-Year Estimates
Households43,243American Community Survey 2020-2024 5-Year Estimates
Housing units46,094American 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
-49
1,024 births, 1,073 deaths
Net migration
-6
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 Fond du Lac 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
Dodge CountyWisconsin30 mi89,097
Winnebago CountyWisconsin27 mi174,218
Sheboygan CountyWisconsin24 mi118,047
Green Lake CountyWisconsin18 mi19,305
Calumet CountyWisconsin15 mi53,982
Washington CountyWisconsin12 mi139,238

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

All 72 counties of Wisconsin

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

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