County Maps US

Marathon County, Wisconsin

The largest of Wisconsin's 72 counties by land area.

CountyFIPS 55073

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

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Population
139,432
+1,313 (+1.0%) since 2020
Land area
1,545
square miles. A further 2.0% of the total area is water
Population density
90.2
people per square mile, computed rather than published
County seat
Wausau
Seat of county government.
Established
1850
175 years ago
Largest city
Wausau city
Population 40,188.

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 Marathon 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 Marathon 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 491 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 Marathon 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
Population139,43210th of 72484th of 3,144
Land area1,545 sq mi1st of 72390th of 3,144
Population density90.2 per sq mi23rd of 72993rd of 3,144
Median household income$77,88419th of 72677th of 3,143

Full data for Marathon County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population139,432Vintage 2025 Population Estimates
Population in 2020138,119Vintage 2025 Population Estimates
2020 estimates base?138,063Vintage 2025 Population Estimates
Land area1,545 sq mi2025 Gazetteer Files
Water area31.1 sq mi2025 Gazetteer Files
Total area1,576 sq mi2025 Gazetteer Files
Population density?90.2 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$77,884American Community Survey 2020-2024 5-Year Estimates
Median home value$219,600American Community Survey 2020-2024 5-Year Estimates
Median age41.3American Community Survey 2020-2024 5-Year Estimates
Households57,866American Community Survey 2020-2024 5-Year Estimates
Housing units60,910American 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
+66
1,418 births, 1,352 deaths
Net migration
+267
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 8 areas bordering Marathon 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
Portage CountyWisconsin31 mi71,943
Lincoln CountyWisconsin30 mi28,403
Clark CountyWisconsin24 mi35,052
Shawano CountyWisconsin24 mi41,560
Wood CountyWisconsin23 mi74,060
Taylor CountyWisconsin19 mi20,118
Langlade CountyWisconsin16 mi19,534
Waupaca CountyWisconsina single point51,461

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.