Morgan County area

Morgan County, Indiana covers 409.4 square miles: 403.9 square miles of land and 5.577 square miles of water. Its county seat is Martinsville. An estimated 74,967 people lived there in 2025.

Official Census measurements · GEOID 181092026 Gazetteer · retrieved September 27, 2026
Land area403.9 mi²
Water area5.577 mi²
Population (2025)74,967
People per mi²186

County outline

Generalized outline of Morgan County, Indiana
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 Morgan County is located

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

Area breakdown

Land accounts for 98.6% of Morgan County’s measured area and water for 1.4%. Its combined area converts to 1,060.4 square kilometers or approximately 262,034 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land403.8511,045.969258,464.6
Water5.57714.4443,569.3
Total409.4281,060.414262,033.9

How Morgan County compares

By original Census land area, Morgan County ranks #41 of 92 in Indiana and #2505 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.019 times the Indiana county-equivalent median of 396.4 square miles. It accounts for 1.1% of the combined county land area in the state.

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

Population and density of Morgan County

The Census Bureau estimates that 74,967 people lived in Morgan County on July 1, 2025. That ranks #761 of 3,222 county equivalents nationally and #24 of 92 in Indiana. Since the April 1, 2020 estimates base of 71,776, the population has grown by 3,191 (+4.4%), compared with +2.8% for Indiana as a whole.

With 403.9 square miles of land, that is 186 people per square mile (72 per km²), placing Morgan County #670 nationally for density and #23 in Indiana. The median county equivalent has 47 people per square mile; the Indiana median is 88. Put another way, there are about 3.4 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate71,84272,29072,32673,24574,04574,967
Change—+448+36+919+800+922

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 Morgan County

7 incorporated places lie at least partly in Morgan County. Together they are home to 29,106 people (38.8%); the other 45,861 (61.2%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Martinsville city, with 12,141 residents in the county. Among places with at least 1,000 residents in 2020, Monrovia town grew fastest since then (+51.2%).

Incorporated placePopulation 2025Since 2020Land mi²
Martinsville cityCounty seat12,141+1.7%9.165
Mooresville town10,173+8%6.709
Brooklyn town2,621+4.5%0.99
Monrovia town2,485+51.2%1.928
Morgantown town1,007−1%0.378
Paragon town584+4.5%0.275
Bethany town95+1.1%0.095

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

Metropolitan area

Morgan County is a central county of the Indianapolis-Carmel-Greenwood, IN Metropolitan Statistical Area. Its 11 county equivalents have 2,205,695 residents on 4,086 square miles of land; Morgan County accounts for 9.9% of the land and 3.4% of the residents. By combined land it ranks #71 of 393 metropolitan areas, and #33 by population. It belongs to the Indianapolis-Carmel-Muncie, IN Combined Statistical Area.

County equivalentPopulation 2025Land mi²
Marion County992,196396
Hamilton County387,036394.4
Hendricks County193,510406.9
Johnson County174,262320.4
Madison County135,088451.9
Hancock County90,969306
Boone County80,689422.9
Morgan County74,967403.9
Shelby County45,882411.1
Brown County15,777312
Tipton County15,319260.5

ZIP codes

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

4610646111461134611846120461254615146157461584616046166461804743347456

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 Morgan County

Morgan County shares a land border with 7 county equivalents. It has more land than 5 of them. The largest neighbor is Putnam County (480.5 mi²) and the smallest is Brown County (312 mi²). Together with its neighbors, Morgan County forms a block of 3,099.5 mi² of land, of which it holds 13%.

Map of Morgan County and the 7 county equivalents that border it Johnson County, Indiana: 320.4 mi² landHendricks County, Indiana: 406.9 mi² landMonroe County, Indiana: 394.5 mi² landPutnam County, Indiana: 480.5 mi² landOwen County, Indiana: 385.3 mi² landBrown County, Indiana: 312 mi² landMarion County, Indiana: 396 mi² land
Morgan 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. MorganCompare
Putnam County480.51.2× largerCompare
Hendricks County406.9about the sameCompare
Marion County396about the sameCompare
Monroe County394.5about the sameCompare
Owen County385.3about the sameCompare
Johnson County320.41.3× smallerCompare
Brown County3121.3× smallerCompare

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

Morgan County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.6 times as much. Indiana’s county land could hold about 89 areas the size of Morgan County.

Land area: Morgan County and the closest-sized states
Morgan County403.9 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 20.1 miles (32.3 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 Morgan County?

Morgan County has more land than 717 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Morgan County403.9 mi²
Indiana median396.4 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 Morgan County at #2,551 nationally by total area, 46 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 1.4%, compared with a national county-equivalent median of 1.2% — 0.2 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 Morgan County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2504Walthall County, Mississippi403.9Compare
#2505Morgan County, Indiana403.9This county
#2506Marion County, Ohio403.8Compare

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 39.482646, -86.447457. 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: 1,045,969,855 m²; AWATER: 14,444,967 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 Morgan County?

Morgan County, Indiana has 403.9 square miles (1,046 km²) of land and 5.577 square miles of water, for a total area of 409.4 square miles. It ranks #2505 of 3,222 U.S. county equivalents by land area.

Is Morgan County the largest county in Indiana?

No. Morgan County ranks #41 of 92 in Indiana by land area. The largest is Allen County, with 657.1 square miles of land.

What counties border Morgan County?

Morgan County shares a land border with Johnson County, Hendricks County, Monroe County, Putnam County, Owen County, Brown County, and Marion County.

What is the population of Morgan County?

The Census Bureau estimates Morgan County had 74,967 residents on July 1, 2025, ranking #761 of 3,222 county equivalents. That is 186 people per square mile of land.

What is the county seat of Morgan County?

The county seat of Morgan County is Martinsville.

What cities and towns are in Morgan County?

Morgan County has 7 incorporated places. The most populous five are Martinsville city, Mooresville town, Brooklyn town, Monrovia town, and Morgantown town; 45,861 residents live outside any incorporated place.

Is Morgan County part of a metropolitan area?

Yes. It is a central county of the Indianapolis-Carmel-Greenwood, IN Metropolitan Statistical Area, which has 11 county equivalents and 2,205,695 residents.

How many ZIP codes are in Morgan County?

14 ZIP Code Tabulation Areas have land in Morgan 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 Morgan County compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 2.6 times as much land.

How many acres of land are in Morgan County?

The land measurement converts to approximately 258,465 acres. Including water, total area is approximately 262,034 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