Marshall County area

Marshall County, Indiana covers 449.7 square miles: 443.6 square miles of land and 6.125 square miles of water. Its county seat is Plymouth. An estimated 46,599 people lived there in 2025.

Official Census measurements · GEOID 180992026 Gazetteer · retrieved September 27, 2026
Land area443.6 mi²
Water area6.125 mi²
Population (2025)46,599
People per mi²105

County outline

Generalized outline of Marshall 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 Marshall County is located

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

Area breakdown

Land accounts for 98.6% of Marshall County’s measured area and water for 1.4%. Its combined area converts to 1,164.8 square kilometers or approximately 287,836 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land443.6181,148.965283,915.5
Water6.12515.8643,920
Total449.7431,164.829287,835.5

How Marshall County compares

By original Census land area, Marshall County ranks #24 of 92 in Indiana and #2291 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.119 times the Indiana county-equivalent median of 396.4 square miles. It accounts for 1.2% of the combined county land area in the state.

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

Population and density of Marshall County

The Census Bureau estimates that 46,599 people lived in Marshall County on July 1, 2025. That ranks #1,074 of 3,222 county equivalents nationally and #32 of 92 in Indiana. Since the April 1, 2020 estimates base of 46,079, the population has grown by 520 (+1.1%), compared with +2.8% for Indiana as a whole.

With 443.6 square miles of land, that is 105 people per square mile (41 per km²), placing Marshall County #949 nationally for density and #38 in Indiana. The median county equivalent has 47 people per square mile; the Indiana median is 88. Put another way, there are about 6.1 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate46,06446,10646,32146,26946,53846,599
Change—+42+215−52+269+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 Marshall County

6 incorporated places lie at least partly in Marshall County. Together they are home to 20,831 people (44.7%); the other 25,768 (55.3%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Plymouth city, with 11,081 residents in the county. Among places with at least 1,000 residents in 2020, Culver town grew fastest since then (+11.2%).

Incorporated placePopulation 2025Since 2020Land mi²
Plymouth cityCounty seat11,081+8.6%7.571
Bremen town4,592−2%2.834
Argos town1,761−0.8%1.286
Bourbon town1,674−1.5%1.151
Culver town1,256+11.2%1.167
La Paz town467−1.3%0.388

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

Metropolitan area

Marshall County is a central county of the Plymouth, IN Micropolitan Statistical Area. Marshall County is the area’s only county equivalent, so the micro area has the same 443.6 square miles of land. By combined land it ranks #457 of 542 micropolitan areas, and #251 by population. It belongs to the South Bend-Elkhart-Mishawaka, IN-MI Combined Statistical Area.

ZIP codes

15 ZIP Code Tabulation Areas have land in Marshall County; 9 of them have most of their land inside the county, and the others mainly cover neighboring areas.

465014650446506465114651346524465314653646537465394655046563465704657246574

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 Marshall County

Marshall County shares a land border with 5 county equivalents. It has more land than 2 of them. The largest neighbor is Kosciusko County (531.4 mi²) and the smallest is Starke County (309.1 mi²). Together with its neighbors, Marshall County forms a block of 2,573.5 mi² of land, of which it holds 17.2%.

Map of Marshall County and the 5 county equivalents that border it St. Joseph County, Indiana: 457.8 mi² landFulton County, Indiana: 368.4 mi² landStarke County, Indiana: 309.1 mi² landKosciusko County, Indiana: 531.4 mi² landElkhart County, Indiana: 463.2 mi² land
Marshall 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. MarshallCompare
Kosciusko County531.41.2× largerCompare
Elkhart County463.2about the sameCompare
St. Joseph County457.8about the sameCompare
Fulton County368.41.2× smallerCompare
Starke County309.11.4× smallerCompare

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

Marshall County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.3 times as much. Indiana’s county land could hold about 81 areas the size of Marshall County.

Land area: Marshall County and the closest-sized states
Marshall County443.6 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 21.1 miles (33.9 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 Marshall County?

Marshall County has more land than 931 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Marshall County443.6 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 Marshall County at #2,346 nationally by total area, 55 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 Marshall County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2290Crawford County, Illinois443.6Compare
#2291Marshall County, Indiana443.6This county
#2292Brantley County, Georgia443.2Compare

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 41.325003, -86.269036. 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: 1,148,964,730 m²; AWATER: 15,863,826 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 Marshall County?

Marshall County, Indiana has 443.6 square miles (1,149 km²) of land and 6.125 square miles of water, for a total area of 449.7 square miles. It ranks #2291 of 3,222 U.S. county equivalents by land area.

Is Marshall County the largest county in Indiana?

No. Marshall County ranks #24 of 92 in Indiana by land area. The largest is Allen County, with 657.1 square miles of land.

What counties border Marshall County?

Marshall County shares a land border with St. Joseph County, Fulton County, Starke County, Kosciusko County, and Elkhart County.

What is the population of Marshall County?

The Census Bureau estimates Marshall County had 46,599 residents on July 1, 2025, ranking #1,074 of 3,222 county equivalents. That is 105 people per square mile of land.

What is the county seat of Marshall County?

The county seat of Marshall County is Plymouth.

What cities and towns are in Marshall County?

Marshall County has 6 incorporated places. The most populous five are Plymouth city, Bremen town, Argos town, Bourbon town, and Culver town; 25,768 residents live outside any incorporated place.

Is Marshall County part of a metropolitan area?

Yes. It is a central county of the Plymouth, IN Micropolitan Statistical Area.

How many ZIP codes are in Marshall County?

15 ZIP Code Tabulation Areas have land in Marshall County, and 9 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

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

It has less land than every state. Rhode Island, the smallest, has 2.3 times as much land.

How many acres of land are in Marshall County?

The land measurement converts to approximately 283,916 acres. Including water, total area is approximately 287,836 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