Madison County area

Madison County, Ohio covers 467.5 square miles: 466.7 square miles of land and 0.822 square miles of water. Its county seat is London. An estimated 46,985 people lived there in 2025.

Official Census measurements · GEOID 390972026 Gazetteer · retrieved September 27, 2026
Land area466.7 mi²
Water area0.822 mi²
Population (2025)46,985
People per mi²101

County outline

Generalized outline of Madison County, Ohio
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 Madison County is located

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

Area breakdown

Land accounts for 99.8% of Madison County’s measured area and water for 0.2%. Its combined area converts to 1,210.8 square kilometers or approximately 299,206 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land466.6881,208.716298,680.3
Water0.8222.129526.1
Total467.511,210.845299,206.4

How Madison County compares

By original Census land area, Madison County ranks #33 of 88 in Ohio and #2205 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.07 times the Ohio county-equivalent median of 436 square miles. It accounts for 1.1% of the combined county land area in the state.

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

Population and density of Madison County

The Census Bureau estimates that 46,985 people lived in Madison County on July 1, 2025. That ranks #1,065 of 3,222 county equivalents nationally and #51 of 88 in Ohio. Since the April 1, 2020 estimates base of 43,855, the population has grown by 3,130 (+7.1%), compared with +0.9% for Ohio as a whole.

With 466.7 square miles of land, that is 101 people per square mile (39 per km²), placing Madison County #990 nationally for density and #55 in Ohio. The median county equivalent has 47 people per square mile; the Ohio median is 120. Put another way, there are about 6.4 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate43,86444,43543,56944,59145,78846,985
Change—+571−866+1,022+1,197+1,197

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 Madison County

6 incorporated places lie at least partly in Madison County. Together they are home to 22,880 people (48.7%); the other 24,105 (51.3%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is London city, with 10,813 residents in the county. By land, West Jefferson village is the largest at 10.5 mi². Among places with at least 1,000 residents in 2020, West Jefferson village grew fastest since then (+40.6%).

Incorporated placePopulation 2025Since 2020Land mi²
London cityCounty seat10,813+5.3%8.397
West Jefferson village5,827+40.6%10.5
Plain City villageAlso in 1 other county3,592+6.1%4.449
Mount Sterling village2,051+5.6%1.688
South Solon village3270%0.235
Midway village2700%0.26

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

Metropolitan area

Madison County is an outlying county of the Columbus, OH Metropolitan Statistical Area. Its 10 county equivalents have 2,242,028 residents on 4,797.5 square miles of land; Madison County accounts for 9.7% of the land and 2.1% of the residents. By combined land it ranks #55 of 393 metropolitan areas, and #32 by population. It belongs to the Columbus-Marion-Zanesville, OH Combined Statistical Area.

County equivalentPopulation 2025Land mi²
Franklin County1,361,536532.4
Delaware County242,032443.1
Licking County185,564682.4
Fairfield County169,752504.4
Union County73,446431.7
Pickaway County62,978501.3
Madison County46,985466.7
Morrow County36,305406.1
Perry County35,918407.9
Hocking County27,512421.4

ZIP codes

12 ZIP Code Tabulation Areas have land in Madison County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.

430264302943044430644311943140431434314643151431534316245369

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 Madison County

Madison County shares a land border with 7 county equivalents. It has more land than 5 of them. The largest neighbor is Franklin County (532.4 mi²) and the smallest is Clark County (395.9 mi²). Together with its neighbors, Madison County forms a block of 3,576.9 mi² of land, of which it holds 13%.

Map of Madison County and the 7 county equivalents that border it Franklin County, Ohio: 532.4 mi² landFayette County, Ohio: 406.4 mi² landClark County, Ohio: 395.9 mi² landUnion County, Ohio: 431.7 mi² landPickaway County, Ohio: 501.3 mi² landChampaign County, Ohio: 429 mi² landGreene County, Ohio: 413.6 mi² land
Madison 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. MadisonCompare
Franklin County532.41.1× largerCompare
Pickaway County501.31.1× largerCompare
Union County431.71.1× smallerCompare
Champaign County4291.1× smallerCompare
Greene County413.61.1× smallerCompare
Fayette County406.41.1× smallerCompare
Clark County395.91.2× smallerCompare

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

Madison County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.2 times as much. Ohio’s county land could hold about 88 areas the size of Madison County.

Land area: Madison County and the closest-sized states
Madison County466.7 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 21.6 miles (34.8 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 Madison County?

Madison County has more land than 1,017 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Madison County466.7 mi²
Ohio median436 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 Madison County at #2,293 nationally by total area, 88 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 0.2%, compared with a national county-equivalent median of 1.2% — 1 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 Madison County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2204Yalobusha County, Mississippi467.2Compare
#2205Madison County, Ohio466.7This county
#2206Butler County, Ohio466.5Compare

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 39.896594, -83.400885. 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: 1,208,715,781 m²; AWATER: 2,129,637 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 Madison County?

Madison County, Ohio has 466.7 square miles (1,208.7 km²) of land and 0.822 square miles of water, for a total area of 467.5 square miles. It ranks #2205 of 3,222 U.S. county equivalents by land area.

Is Madison County the largest county in Ohio?

No. Madison County ranks #33 of 88 in Ohio by land area. The largest is Ashtabula County, with 702.4 square miles of land.

What counties border Madison County?

Madison County shares a land border with Franklin County, Fayette County, Clark County, Union County, Pickaway County, Champaign County, and Greene County.

What is the population of Madison County?

The Census Bureau estimates Madison County had 46,985 residents on July 1, 2025, ranking #1,065 of 3,222 county equivalents. That is 101 people per square mile of land.

What is the county seat of Madison County?

The county seat of Madison County is London.

What cities and towns are in Madison County?

Madison County has 6 incorporated places. The most populous five are London city, West Jefferson village, Plain City village, Mount Sterling village, and South Solon village; 24,105 residents live outside any incorporated place.

Is Madison County part of a metropolitan area?

Yes. It is an outlying county of the Columbus, OH Metropolitan Statistical Area, which has 10 county equivalents and 2,242,028 residents.

How many ZIP codes are in Madison County?

12 ZIP Code Tabulation Areas have land in Madison County, and 7 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

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

It has less land than every state. Rhode Island, the smallest, has 2.2 times as much land.

How many acres of land are in Madison County?

The land measurement converts to approximately 298,680 acres. Including water, total area is approximately 299,206 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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