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County · code 55139

Winnebago CountyWisconsin

Winnebago County is in Wisconsin, with its seat in Oshkosh. The county was created by Wisconsin Territory on January 6, 1840, from parts of Brown, Calumet, Fond du Lac, and Marquette counties.

  • Founded1840
  • County seatOshkosh
  • Named forHo-Chunk
  • Land area435 sq mi + 144 sq mi water
  • Population171,730 2020 Census
  • Parcels mapped80,772 checked 14 October 2026
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Updated

Fond du LacCalumetWaushara Oshkosh Census outline · seat marked

Where it is

Winnebago on the map of Wisconsin

Wisconsin has 72 counties and county equivalents, each with its own records office. Shapes with a page are links.

Adams CountyAshland CountyBarron CountyBayfield CountyBrown CountyBuffalo CountyBurnett CountyCalumet CountyChippewa CountyClark CountyColumbia CountyCrawford CountyDane CountyDodge CountyDoor CountyDouglas CountyDunn CountyEau Claire CountyFlorence CountyFond du Lac CountyForest CountyGrant CountyGreen CountyGreen Lake CountyIowa CountyIron CountyJackson CountyJefferson CountyJuneau CountyKenosha CountyKewaunee CountyLa Crosse CountyLafayette CountyLanglade CountyLincoln CountyManitowoc CountyMarathon CountyMarinette CountyMarquette CountyMenominee CountyMilwaukee CountyMonroe CountyOconto CountyOneida CountyOutagamie CountyOzaukee CountyPepin CountyPierce CountyPolk CountyPortage CountyPrice CountyRacine CountyRichland CountyRock CountyRusk CountySt. Croix CountySauk CountySawyer CountyShawano CountySheboygan CountyTaylor CountyTrempealeau CountyVernon CountyVilas CountyWalworth CountyWashburn CountyWashington CountyWaukesha CountyWaupaca CountyWaushara CountyWood CountyWinnebago County Winnebago
Counties of Wisconsin · Winnebago highlighted

History

Formed in 1840 from Brown County, Calumet County, Fond du Lac County and Marquette County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Winnebago County was formed from Brown, Calumet, Fond du Lac, and Marquette counties and named after the Ho-Chunk people. The county went through several boundary changes in its early years, including gaining and losing territory to Fond du Lac, Brown, Outagamie, Waupaca, Portage, and Shawano counties between 1840 and 1853. Winnebago became fully organized and detached from Fond du Lac on January 1, 1848, and was admitted as a state county on May 29, 1848.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

  1. 1840
    Winnebago County created Winnebago created by Wisconsin Territory from Brown, Calumet, Fond du Lac, and the northern part of Overlap Area 2 jointly claimed by Fond du Lac and Marquette; Winnebago not fully organized, attached to Brown "for judicial purposes."
    from Brownfrom Calumetfrom Fond du Lacfrom Marquette
    · Wis. Terr. Laws 1839-1840, no. 12, secs. 8-10/pp. 18-20; Wis. Terr. Laws 1841-1842, p. 74
  2. 1844
    Lost territory Winnebago lost to Fond du Lac.
    to Fond du Lac.
    · Wis. Terr. Laws 1843-1844, pp. 8-11
  3. 1848
    Gained territory Winnebago gained from Fond du Lac.
    from Fond du Lac.
    · Wis. Terr. Laws 1848, pp. 79-80
  4. 1848
    Became part of Wisconsin Winnebago became a county in the state of Wisconsin. · U.S. Stat., vol. 9, ch. 89 [1846]/pp. 56-58, and ch. 50 [1848]/pp. 233-235; Van Zandt, 128, 130
  5. 1849
    Gained territory Winnebago gained from Brown.
    from Brown
    · Wis. Laws 1849, ch. 79, secs. 1-2/p. 49; Wis. Rev. Stat., 1849, ch. 2, secs. 3, 30/pp. 51, 57-58
Show all 15 changes (10 more)
  1. 1840
    Winnebago County created Winnebago created by Wisconsin Territory from Brown, Calumet, Fond du Lac, and the northern part of Overlap Area 2 jointly claimed by Fond du Lac and Marquette; Winnebago not fully organized, attached to Brown "for judicial purposes."
    from Brownfrom Calumetfrom Fond du Lacfrom Marquette
    · Wis. Terr. Laws 1839-1840, no. 12, secs. 8-10/pp. 18-20; Wis. Terr. Laws 1841-1842, p. 74
  2. 1842
    Changed Winnebago organized "for all purposes of county government;" remained attached to Brown "for judicial purposes."
    Brown
    · Wis. Terr. Laws 1841-1842, p. 74
  3. 1844
    Lost territory Winnebago lost to Fond du Lac.
    to Fond du Lac.
    · Wis. Terr. Laws 1843-1844, pp. 8-11
  4. 1844
    Changed Winnebago detached from Brown, attached to Fond du Lac "for judicial purposes."
    BrownFond du Lac
    · Harney, 120-121; Wis. Terr. Laws 1843-1844, pp. 10-11
  5. 1848
    Changed Winnebago fully organized, detached from Fond du Lac.
    Fond du Lac.
    · Harney, 121; Wis. Terr. Laws 1847, reg. sess., p. 96
  6. 1848
    Gained territory Winnebago gained from Fond du Lac.
    from Fond du Lac.
    · Wis. Terr. Laws 1848, pp. 79-80
  7. 1848
    Became part of Wisconsin Winnebago became a county in the state of Wisconsin. · U.S. Stat., vol. 9, ch. 89 [1846]/pp. 56-58, and ch. 50 [1848]/pp. 233-235; Van Zandt, 128, 130
  8. 1849
    Gained territory Winnebago gained from Brown.
    from Brown
    · Wis. Laws 1849, ch. 79, secs. 1-2/p. 49; Wis. Rev. Stat., 1849, ch. 2, secs. 3, 30/pp. 51, 57-58
  9. 1851
    Lost territory Winnebago lost to creation of Outagamie and Waupaca; Waupaca not fully organized, attached to Winnebago "for judicial purposes." Winnebago was separated into two parts by these creations.
    to Outagamieto Waupaca
    · Wis. Laws 1851, chs. 78, 83/pp. 57, 60-61
  10. 1851
    Lost territory Winnebago lost to Portage.
    to Portage
    · Wis. Laws 1851, ch. 114, sec. 1/pp. 96-97
  11. 1853
    Lost territory Winnebago lost to creation of Shawano.
    to Shawano
    · Wis. Laws 1853, gen., ch. 9, sec. 1/pp. 9-10
  12. 1853
    Changed Waupaca fully organized, detached from Winnebago.
    Waupaca
    · Wis. Laws 1853, gen., ch. 7, sec. 1/pp. 6-7
  13. 1854
    Lost territory Winnebago lost to Shawano.
    to Shawano
    · Wis. Laws 1854, gen., ch. 23, secs. 1, 3-4/pp. 31-32
  14. 1855
    Changed Legislature authorized Winnebago to hold a referendum on retaining the five townships that were transferred from Winnebago to Portage on 27 February 1851 (townships 21-25 north, range 10 east). No explanation for this apparent oversight has been found, and there is no evidence that the referendum was held (no change).
    Portage
    · Wis. Laws 1855, gen., ch. 51, secs. 1-4/pp. 50-51
  15. 1856
    Lost territory Winnebago lost to Oconto and Shawano; Winnebago no longer divided into two parts.
    to Ocontoto Shawano
    · Wis. Laws 1856, reg. sess., gen., ch. 45, secs. 1-4/p. 48

Land and parcels

What the maps cover in Winnebago

Who publishes each layer, how good it is, and when we last checked.

Official
from the office that keeps the record
Good enough
a reliable statewide or national copy
Fallback
a guide only; check the official record
Missing
nothing public found yet

People and land

Winnebago by the Census

Population
171,730 2020 Census count
Housing units
76,046 2020 Census count
Land area
435 square miles
Water area
144 square miles
People per sq mi
395 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Winnebago County's official site

We have found the county's site but not its offices yet; start there.

County government

See your own lot on these maps

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Questions

Common questions about Winnebago County

When was Winnebago County founded?
Winnebago County was founded in 1840, formed from Brown County, Calumet County, Fond du Lac County and Marquette County, and named after Ho-Chunk.
What is the county seat of Winnebago County?
The county seat of Winnebago County is Oshkosh.
Is there an online parcel map for Winnebago County?
Yes. Wisconsin DOA, Wisconsin Land Information Program, with the State Cartographer's Office (V12 Statewide Parcels) publishes a parcel map of 80,772 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Winnebago County's boundary or name changed?
Winnebago County was created in 1840 from Brown County, Calumet County, Fond du Lac County and Marquette County. Since then the Atlas of Historical County Boundaries records 14 later changes, chiefly involving Brown County, Fond du Lac. County and Shawano County.
Is my lot in a flood zone?
We do not have flood maps for Winnebago County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Counties next door