Menard County area

Menard County, Illinois covers 315.4 square miles: 314.4 square miles of land and 1.019 square miles of water. Its county seat is Petersburg. An estimated 11,863 people lived there in 2025.

Official Census measurements · GEOID 171292026 Gazetteer · retrieved September 27, 2026
Land area314.4 mi²
Water area1.019 mi²
Population (2025)11,863
People per mi²38

County outline

Generalized outline of Menard County, Illinois
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 Menard County is located

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

Area breakdown

Land accounts for 99.7% of Menard County’s measured area and water for 0.3%. Its combined area converts to 816.9 square kilometers or approximately 201,862 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land314.391814.269201,210.2
Water1.0192.639652.2
Total315.41816.908201,862.4

How Menard County compares

By original Census land area, Menard County ranks #90 of 102 in Illinois and #2775 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.616 times the Illinois county-equivalent median of 510.7 square miles. It accounts for 0.6% of the combined county land area in the state.

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

Population and density of Menard County

The Census Bureau estimates that 11,863 people lived in Menard County on July 1, 2025. That ranks #2,360 of 3,222 county equivalents nationally and #83 of 102 in Illinois. Since the April 1, 2020 estimates base of 12,297, the population has declined by 434 (−3.5%), compared with −0.8% for Illinois as a whole.

With 314.4 square miles of land, that is 38 people per square mile (15 per km²), placing Menard County #1,802 nationally for density and #63 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 17 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate12,27312,17412,07412,00911,92411,863
Change—−99−100−65−85−61

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Menard County

5 incorporated places lie at least partly in Menard County. Together they are home to 5,370 people (45.3%); the other 6,493 (54.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Petersburg city, with 2,125 residents in the county. By land, Athens city is the largest at 1.684 mi².

Incorporated placePopulation 2025Since 2020Land mi²
Petersburg cityCounty seat2,125−4.2%1.562
Athens city1,883−4.4%1.684
Greenview village718−4.1%0.859
Tallula village420−3.4%0.531
Oakford village224−3.9%0.249

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Menard County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Menard County is an outlying county of the Springfield, IL Metropolitan Statistical Area. Its 2 county equivalents have 206,033 residents on 1,182.6 square miles of land; Menard County accounts for 26.6% of the land and 5.8% of the residents. By combined land it ranks #261 of 393 metropolitan areas, and #234 by population. It belongs to the Springfield-Jacksonville-Lincoln, IL Combined Statistical Area.

County equivalentPopulation 2025Land mi²
Sangamon County194,170868.2
Menard County11,863314.4

ZIP codes

8 ZIP Code Tabulation Areas have land in Menard County; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.

6261362642626666267362675626776268862693

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Menard County

Menard County shares a land border with 4 county equivalents. Each of them has more land than Menard County. The largest neighbor is Sangamon County (868.2 mi²) and the smallest is Cass County (375.8 mi²). Together with its neighbors, Menard County forms a block of 2,715.8 mi² of land, of which it holds 11.6%.

Map of Menard County and the 4 county equivalents that border it Sangamon County, Illinois: 868.2 mi² landMason County, Illinois: 539.4 mi² landCass County, Illinois: 375.8 mi² landLogan County, Illinois: 618.1 mi² land
Menard County (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. MenardCompare
Sangamon County868.22.8× largerCompare
Logan County618.12× largerCompare
Mason County539.41.7× largerCompare
Cass County375.81.2× largerCompare

How big is Menard County compared with U.S. states?

Menard County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 3.3 times as much. Illinois’s county land could hold about 177 areas the size of Menard County.

Land area: Menard County and the closest-sized states
Menard County314.4 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 17.7 miles (28.5 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Menard County?

Menard County has more land than 447 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Menard County314.4 mi²
Illinois median510.7 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 Menard County at #2,811 nationally by total area, 36 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.3%, compared with a national county-equivalent median of 1.2% — 0.8 percentage points lower. 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 Menard County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2774King and Queen County, Virginia315.1Compare
#2775Menard County, Illinois314.4This county
#2776Smith County, Tennessee314.3Compare

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 40.022569, -89.794133. 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: 814,269,349 m²; AWATER: 2,640,419 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 big is Menard County?

Menard County, Illinois has 314.4 square miles (814.3 km²) of land and 1.019 square miles of water, for a total area of 315.4 square miles. It ranks #2775 of 3,222 U.S. county equivalents by land area.

Is Menard County the largest county in Illinois?

No. Menard County ranks #90 of 102 in Illinois by land area. The largest is McLean County, with 1,183.2 square miles of land.

What counties border Menard County?

Menard County shares a land border with Sangamon County, Mason County, Cass County, and Logan County.

What is the population of Menard County?

The Census Bureau estimates Menard County had 11,863 residents on July 1, 2025, ranking #2,360 of 3,222 county equivalents. That is 38 people per square mile of land.

What is the county seat of Menard County?

The county seat of Menard County is Petersburg.

What cities and towns are in Menard County?

Menard County has 5 incorporated places. The most populous are Petersburg city, Athens city, Greenview village, Tallula village, and Oakford village; 6,493 residents live outside any incorporated place.

Is Menard County part of a metropolitan area?

Yes. It is an outlying county of the Springfield, IL Metropolitan Statistical Area, which has 2 county equivalents and 206,033 residents.

How many ZIP codes are in Menard County?

8 ZIP Code Tabulation Areas have land in Menard County, and 5 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does Menard County compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 3.3 times as much land.

How many acres of land are in Menard County?

The land measurement converts to approximately 201,210 acres. Including water, total area is approximately 201,862 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