WI · GEOID 55139

Winnebago County area

Winnebago County, Wisconsin covers 578.6 square miles: 434.7 square miles of land and 143.9 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area434.7 mi²
Water area143.9 mi²
Total area578.6 mi²
National land rank#2331

County outline

Generalized outline of Winnebago County, Wisconsin
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Winnebago County is located

Winnebago County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 75.1% of Winnebago County’s measured area and water for 24.9%. Its combined area converts to 1,498.5 square kilometers or approximately 370,285 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land434.6971,125.86278,206.1
Water143.873372.62992,078.7
Total578.571,498.489370,284.8

How Winnebago County compares

By original Census land area, Winnebago County ranks #62 of 72 in Wisconsin and #2331 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.577 times the Wisconsin county-equivalent median of 753 square miles. It accounts for 0.8% of the combined county land area in the state.

See the complete Wisconsin ranking · What counts as a county equivalent?

What stands out about Winnebago County?

Winnebago County has more land than 891 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Winnebago County434.7 mi²
Wisconsin median753 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Winnebago County at #1,842 nationally by total area, 489 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 24.9%, compared with a national county-equivalent median of 1.2% — 23.7 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Winnebago County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2330Watonwan County, Minnesota435Compare
#2331Winnebago County, Wisconsin434.7This county
#2332Beaver County, Pennsylvania434.7Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 44.085707, -88.668149. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,125,861,120 m²; AWATER: 372,630,371 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Winnebago County?

The land measurement converts to approximately 278,206 acres. Including water, total area is approximately 370,285 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset