County · code 17201
Winnebago CountyIllinois
Winnebago County is a county in Illinois with its seat in Rockford, formed in 1836.
- Founded1836
- County seatRockford
- Named forHo-Chunk
- Land area513 sq mi + 6.1 sq mi water
- Population285,350 2020 Census
- Parcels mapped127,957 checked 16 October 2026
Where it is
Winnebago on the map of Illinois
Illinois has 102 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1836 from Jo Daviess County and La Salle County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Winnebago County was created on January 16, 1836, from parts of Jo Daviess County and Non-County Area, with land from the county later attached to La Salle County. The county was named after the Ho-Chunk people. Winnebago County lost territory in 1837 with the creation of Boone and Stephenson counties, and lost additional land to Boone County in 1843.
- 1836Winnebago County created Winnebago created from Jo Daviess and Non-County Area 8 attached to La Salle.from Jo Daviessfrom La Salle· Ill. Laws 1835-1836, 273-278
- 1837Lost territory Winnebago lost to creation of Boone and Stephenson. · Ill. Laws 1836-1837, pp. 96-100
- 1843
Land and parcels
What the maps cover in Winnebago
Who publishes each layer, how good it is, and when we last checked.
-
Parcels Good enough
Lot lines and tax-map numbers for 127,957 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 16 October 2026 -
Address points Missing
No public address points layer found for Winnebago County yet.
-
Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- 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
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
- County government
The official website of Winnebago County.
See your own lot on these maps
Open Winnebago County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Winnebago County
- When was Winnebago County founded?
- Winnebago County was founded in 1836, formed from Jo Daviess County and La Salle County, and named after Ho-Chunk.
- What is the county seat of Winnebago County?
- The county seat of Winnebago County is Rockford.
- Is there an online parcel map for Winnebago County?
- Yes. A public source publishes a parcel map of 127,957 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 1836 from Jo Daviess County and La Salle County. Since then the Atlas of Historical County Boundaries records 2 later changes, chiefly involving Boone County and Stephenson 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