Massac County area

Massac County, Illinois covers 242.1 square miles: 237.2 square miles of land and 4.935 square miles of water. Its county seat is Metropolis. An estimated 13,502 people lived there in 2025.

Official Census measurements · GEOID 171272026 Gazetteer · retrieved September 27, 2026
Land area237.2 mi²
Water area4.935 mi²
Population (2025)13,502
People per mi²57

County outline

Generalized outline of Massac 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 Massac County is located

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

Area breakdown

Land accounts for 98% of Massac County’s measured area and water for 2%. Its combined area converts to 627 square kilometers or approximately 154,936 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land237.152614.221151,777.3
Water4.93512.7823,158.4
Total242.087627.002154,935.7

How Massac County compares

By original Census land area, Massac County ranks #96 of 102 in Illinois and #2935 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.464 times the Illinois county-equivalent median of 510.7 square miles. It accounts for 0.4% of the combined county land area in the state.

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

Population and density of Massac County

The Census Bureau estimates that 13,502 people lived in Massac County on July 1, 2025. That ranks #2,260 of 3,222 county equivalents nationally and #76 of 102 in Illinois. Since the April 1, 2020 estimates base of 14,176, the population has declined by 674 (−4.8%), compared with −0.8% for Illinois as a whole.

With 237.2 square miles of land, that is 57 people per square mile (22 per km²), placing Massac County #1,435 nationally for density and #43 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 11 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate14,14113,95913,86313,74113,61613,502
Change—−182−96−122−125−114

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 Massac County

3 incorporated places lie at least partly in Massac County. Together they are home to 6,748 people (50%); the other 6,754 (50%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Metropolis city, with 5,727 residents in the county.

Incorporated placePopulation 2025Since 2020Land mi²
Metropolis cityCounty seat5,727−3.9%6.008
Brookport city691−4.7%0.653
Joppa village330−5.4%0.486

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

Metropolitan area

Massac County is an outlying county of the Paducah, KY-IL Metropolitan Statistical Area. Its 5 county equivalents have 102,259 residents on 1,235.5 square miles of land; Massac County accounts for 19.2% of the land and 13.2% of the residents. By combined land it ranks #252 of 393 metropolitan areas, and #364 by population. It belongs to the Paducah-Mayfield, KY-IL Combined Statistical Area.

County equivalentPopulation 2025Land mi²
McCracken CountyKentucky67,553248.8
Massac County13,502237.2
Livingston CountyKentucky8,863313
Ballard CountyKentucky7,594247.1
Carlisle CountyKentucky4,747189.5

ZIP codes

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

6290862910629386294162943629536295662960

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 Massac County

Massac County shares a land border with 5 county equivalents, including 2 in Kentucky. It has more land than 1 of them. The largest neighbor is Pope County (368.9 mi²) and the smallest is Pulaski County (199.3 mi²). Together with its neighbors, Massac County forms a block of 1,710.8 mi² of land, of which it holds 13.9%.

Map of Massac County and the 5 county equivalents that border it Pope County, Illinois: 368.9 mi² landMcCracken County, Kentucky: 248.8 mi² landJohnson County, Illinois: 343.7 mi² landPulaski County, Illinois: 199.3 mi² landLivingston County, Kentucky: 313 mi² land
Massac 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. MassacCompare
Pope County368.91.6× largerCompare
Johnson County343.71.4× largerCompare
Livingston CountyKentucky3131.3× largerCompare
McCracken CountyKentucky248.8about the sameCompare
Pulaski County199.31.2× smallerCompare

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

Massac County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 4.4 times as much. Illinois’s county land could hold about 234 areas the size of Massac County.

Land area: Massac County and the closest-sized states
Massac County237.2 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 15.4 miles (24.8 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 Massac County?

Massac County has more land than 287 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Massac County237.2 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 Massac County at #2,966 nationally by total area, 31 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 2%, compared with a national county-equivalent median of 1.2% — 0.9 percentage points higher. 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 Massac County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2934Seminole County, Georgia237.6Compare
#2935Massac County, Illinois237.2This county
#2936Clay County, Tennessee236.5Compare

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 37.216119, -88.705658. 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: 614,222,109 m²; AWATER: 12,780,833 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 Massac County?

Massac County, Illinois has 237.2 square miles (614.2 km²) of land and 4.935 square miles of water, for a total area of 242.1 square miles. It ranks #2935 of 3,222 U.S. county equivalents by land area.

Is Massac County the largest county in Illinois?

No. Massac County ranks #96 of 102 in Illinois by land area. The largest is McLean County, with 1,183.2 square miles of land.

What counties border Massac County?

Massac County shares a land border with Pope County, McCracken County, Kentucky, Johnson County, Pulaski County, and Livingston County, Kentucky.

What is the population of Massac County?

The Census Bureau estimates Massac County had 13,502 residents on July 1, 2025, ranking #2,260 of 3,222 county equivalents. That is 57 people per square mile of land.

What is the county seat of Massac County?

The county seat of Massac County is Metropolis.

What cities and towns are in Massac County?

Massac County has 3 incorporated places. The most populous are Metropolis city, Brookport city, and Joppa village; 6,754 residents live outside any incorporated place.

Is Massac County part of a metropolitan area?

Yes. It is an outlying county of the Paducah, KY-IL Metropolitan Statistical Area, which has 5 county equivalents and 102,259 residents.

How many ZIP codes are in Massac County?

8 ZIP Code Tabulation Areas have land in Massac 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 Massac County compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 4.4 times as much land.

How many acres of land are in Massac County?

The land measurement converts to approximately 151,777 acres. Including water, total area is approximately 154,936 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

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