County Maps US

Menard County, Illinois

A county in Illinois, ranked 83 of 102 by population.

CountyFIPS 17129

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

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Population
11,863
-410 (-3.3%) since 2020
Land area
314.4
square miles. A further 0.3% of the total area is water
Population density
37.7
people per square mile, computed rather than published
County seat
Petersburg
Seat of county government.
Established
1839
186 years ago
Largest city
Petersburg city
Population 2,125.

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 Menard 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 Menard County, Illinois 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 666 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 Menard County ranks

Position among the 102 counties of Illinois, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn IllinoisNationally
Population11,86383rd of 1022,290th of 3,144
Land area314.4 sq mi90th of 1022,775th of 3,144
Population density37.7 per sq mi63rd of 1021,724th of 3,144
Median household income$82,17615th of 102503rd of 3,143

Full data for Menard County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population11,863Vintage 2025 Population Estimates
Population in 202012,273Vintage 2025 Population Estimates
2020 estimates base?12,297Vintage 2025 Population Estimates
Land area314.4 sq mi2025 Gazetteer Files
Water area1.0 sq mi2025 Gazetteer Files
Total area315.4 sq mi2025 Gazetteer Files
Population density?37.7 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$82,176American Community Survey 2020-2024 5-Year Estimates
Median home value$185,500American Community Survey 2020-2024 5-Year Estimates
Median age42.8American Community Survey 2020-2024 5-Year Estimates
Households5,228American Community Survey 2020-2024 5-Year Estimates
Housing units5,600American 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
-41
119 births, 160 deaths
Net migration
-20
More people moved out than moved in.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 4 areas bordering Menard 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
Mason CountyIllinois41 mi12,411
Sangamon CountyIllinois27 mi194,170
Cass CountyIllinois14 mi12,463
Logan CountyIllinois11 mi27,182

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 102 counties of Illinois

Open the interactive Illinois county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.