County Maps US

Ozaukee County, Wisconsin

A county in Wisconsin, ranked 18 of 72 by population.

CountyFIPS 55089

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

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Population
94,346
+2,715 (+3.0%) since 2020
Land area
233
square miles. A further 79.1% of the total area is water
Population density
405
people per square mile, computed rather than published
County seat
Port Washington
Seat of county government.
Established
1853
172 years ago
Largest city
Mequon city
Population 25,120.

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 Ozaukee 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 Ozaukee 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 488 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 Ozaukee 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
Population94,34618th of 72652nd of 3,144
Land area233 sq mi71st of 722,943rd of 3,144
Population density405 per sq mi7th of 72341st of 3,144
Median household income$96,9963rd of 72201st of 3,143

Full data for Ozaukee County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population94,346Vintage 2025 Population Estimates
Population in 202091,631Vintage 2025 Population Estimates
2020 estimates base?91,504Vintage 2025 Population Estimates
Land area233 sq mi2025 Gazetteer Files
Water area883.2 sq mi2025 Gazetteer Files
Total area1,116 sq mi2025 Gazetteer Files
Population density?405 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$96,996American Community Survey 2020-2024 5-Year Estimates
Median home value$390,200American Community Survey 2020-2024 5-Year Estimates
Median age43.9American Community Survey 2020-2024 5-Year Estimates
Households38,309American Community Survey 2020-2024 5-Year Estimates
Housing units39,872American 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
-105
746 births, 851 deaths
Net migration
+792
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 6 areas bordering Ozaukee 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
Milwaukee CountyWisconsin48 mi924,216
Sheboygan CountyWisconsin45 mi118,047
Washington CountyWisconsin25 mi139,238
Muskegon CountyMichigan19 mi177,901
Oceana CountyMichigan4.9 mi27,177
Waukesha CountyWisconsina single point417,210

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.