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County · code 17109

McDonough CountyIllinois

McDonough County, Illinois is located in the state's west-central region and has its county seat in Macomb. The county was formed on January 25, 1826, and named after Thomas Macdonough.

  • Founded1826
  • County seatMacomb
  • Named forThomas Macdonough
  • Land area589 sq mi + 0.8 sq mi water
  • Population27,238 2020 Census
  • Parcels mapped18,353 checked 15 October 2026
Open the free map Click any parcel in McDonough County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated

SchuylerWarrenHendersonHancock Macomb Census outline · seat marked

Where it is

McDonough on the map of Illinois

Illinois has 102 counties and county equivalents, each with its own records office. Shapes with a page are links.

Adams CountyAlexander CountyBond CountyBoone CountyBrown CountyBureau CountyCalhoun CountyCarroll CountyCass CountyChampaign CountyChristian CountyClark CountyClay CountyClinton CountyColes CountyCook CountyCrawford CountyCumberland CountyDeKalb CountyDe Witt CountyDouglas CountyDuPage CountyEdgar CountyEdwards CountyEffingham CountyFayette CountyFord CountyFranklin CountyFulton CountyGallatin CountyGreene CountyGrundy CountyHamilton CountyHancock CountyHardin CountyHenderson CountyHenry CountyIroquois CountyJackson CountyJasper CountyJefferson CountyJersey CountyJo Daviess CountyJohnson CountyKane CountyKankakee CountyKendall CountyKnox CountyLake CountyLaSalle CountyLawrence CountyLee CountyLivingston CountyLogan CountyMcHenry CountyMcLean CountyMacon CountyMacoupin CountyMadison CountyMarion CountyMarshall CountyMason CountyMassac CountyMenard CountyMercer CountyMonroe CountyMontgomery CountyMorgan CountyMoultrie CountyOgle CountyPeoria CountyPerry CountyPiatt CountyPike CountyPope CountyPulaski CountyPutnam CountyRandolph CountyRichland CountyRock Island CountySt. Clair CountySaline CountySangamon CountySchuyler CountyScott CountyShelby CountyStark CountyStephenson CountyTazewell CountyUnion CountyVermilion CountyWabash CountyWarren CountyWashington CountyWayne CountyWhite CountyWhiteside CountyWill CountyWilliamson CountyWinnebago CountyWoodford CountyMcDonough County McDonough
Counties of Illinois · McDonough highlighted

History

Founded in 1826

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

McDonough County was created from non-county area attached to Schuyler County, though it was not fully organized at first and remained attached to Schuyler for county purposes. On July 3, 1830, McDonough County was fully organized and detached from Schuyler.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

  1. 1826
    McDonough County created McDonough created from Non-County Area 3 attached to Schuyler; McDonough not fully organized, attached to Schuyler "for county purposes."
    from Schuyler
    · Ill. Laws 1826, pp. 76-77
  2. 1830
    Changed McDonough fully organized, detached from Schuyler.
    Schuyler
    · McLean, 624

Land and parcels

What the maps cover in McDonough

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

McDonough by the Census

Population
27,238 2020 Census count
Housing units
13,609 2020 Census count
Land area
589 square miles
Water area
0.8 square miles
People per sq mi
46 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

McDonough 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

Open McDonough 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.

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Questions

Common questions about McDonough County

When was McDonough County founded?
McDonough County was founded in 1826, and named after Thomas Macdonough.
What is the county seat of McDonough County?
The county seat of McDonough County is Macomb.
Is there an online parcel map for McDonough County?
Yes. McDonough County publishes a parcel map of 18,353 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has McDonough County's boundary or name changed?
McDonough County was created in 1826. Since then the Atlas of Historical County Boundaries records 1 later change, chiefly involving Schuyler County.
Is my lot in a flood zone?
We do not have flood maps for McDonough 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