Cass County area

Cass County, Nebraska covers 565.9 square miles: 556.9 square miles of land and 8.98 square miles of water. Its county seat is Plattsmouth. An estimated 27,657 people lived there in 2025.

Official Census measurements · GEOID 310252026 Gazetteer · retrieved September 27, 2026
Land area556.9 mi²
Water area8.98 mi²
Population (2025)27,657
People per mi²50

County outline

Generalized outline of Cass County, Nebraska
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 Cass County is located

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

Area breakdown

Land accounts for 98.4% of Cass County’s measured area and water for 1.6%. Its combined area converts to 1,465.7 square kilometers or approximately 362,170 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land556.9111,442.393356,423
Water8.9823.2585,747.2
Total565.8911,465.651362,170.2

How Cass County compares

By original Census land area, Cass County ranks #67 of 93 in Nebraska and #1862 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.968 times the Nebraska county-equivalent median of 575.2 square miles. It accounts for 0.7% of the combined county land area in the state.

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

Population and density of Cass County

The Census Bureau estimates that 27,657 people lived in Cass County on July 1, 2025. That ranks #1,565 of 3,222 county equivalents nationally and #12 of 93 in Nebraska. Since the April 1, 2020 estimates base of 26,601, the population has grown by 1,056 (+4%), compared with +2.9% for Nebraska as a whole.

With 556.9 square miles of land, that is 50 people per square mile (19 per km²), placing Cass County #1,559 nationally for density and #12 in Nebraska. The median county equivalent has 47 people per square mile; the Nebraska median is 8. Put another way, there are about 13 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate26,61027,08427,17727,46327,50127,657
Change—+474+93+286+38+156

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 Cass County

15 incorporated places lie at least partly in Cass County. Together they are home to 14,153 people (51.2%); the other 13,504 (48.8%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Plattsmouth city, with 6,955 residents in the county. Among places with at least 1,000 residents in 2020, Eagle village grew fastest since then (+10.8%).

Incorporated placePopulation 2025Since 2020Land mi²
Plattsmouth cityCounty seat6,955+5.5%3.314
Louisville city1,419+5.5%0.647
Eagle village1,206+10.8%0.425
Weeping Water city1,061+2.4%1.062
Elmwood village684+2.5%0.451
Greenwood village616+3.2%0.439
Murray village502+2.9%0.356
Cedar Creek village476+2.8%0.532
Murdock village276+2.6%0.129
Union village200+2.6%0.182
Avoca village187+2.7%0.201
Nehawka village178+2.3%0.242
Manley village174+3%0.115
Alvo village125+2.5%0.131
South Bend village94+4.4%0.074

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

Metropolitan area

Cass County is an outlying county of the Omaha, NE-IA Metropolitan Statistical Area. Its 8 county equivalents have 1,009,836 residents on 4,345.7 square miles of land; Cass County accounts for 12.8% of the land and 2.7% of the residents. By combined land it ranks #63 of 393 metropolitan areas, and #57 by population. It belongs to the Omaha-Fremont, NE-IA Combined Statistical Area.

County equivalentPopulation 2025Land mi²
Douglas County606,460326.5
Sarpy County208,303238
Pottawattamie CountyIowa92,996951.3
Cass County27,657556.9
Saunders County23,702748.7
Washington County21,302389.9
Mills CountyIowa14,793437.4
Harrison CountyIowa14,623696.9

ZIP codes

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

6800368016680376804868058683046830768347683496836668403684076840968413684186845468455684626846368527

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 Cass County

Cass County shares a land border with 6 county equivalents, including 2 in Iowa. It has more land than 3 of them. The largest neighbor is Lancaster County (837.6 mi²) and the smallest is Sarpy County (238 mi²). Together with its neighbors, Cass County forms a block of 3,945.4 mi² of land, of which it holds 14.1%.

Map of Cass County and the 6 county equivalents that border it Otoe County, Nebraska: 615.6 mi² landSarpy County, Nebraska: 238 mi² landLancaster County, Nebraska: 837.6 mi² landMills County, Iowa: 437.4 mi² landFremont County, Iowa: 511.2 mi² landSaunders County, Nebraska: 748.7 mi² land
Cass 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. CassCompare
Lancaster County837.61.5× largerCompare
Saunders County748.71.3× largerCompare
Otoe County615.61.1× largerCompare
Fremont CountyIowa511.21.1× smallerCompare
Mills CountyIowa437.41.3× smallerCompare
Sarpy County2382.3× smallerCompare

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

Cass County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.9 times as much. Nebraska’s county land could hold about 138 areas the size of Cass County.

Land area: Cass County and the closest-sized states
Cass County556.9 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 23.6 miles (38 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 Cass County?

Cass County has more land than 1,360 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Cass County556.9 mi²
Nebraska median575.2 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 Cass County at #1,951 nationally by total area, 89 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 1.6%, compared with a national county-equivalent median of 1.2% — 0.4 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 Cass County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#1861Sumter County, Florida557.1Compare
#1862Cass County, Nebraska556.9This county
#1863Jefferson County, Wisconsin556.5Compare

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 40.907942, -96.148194. 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: 1,442,393,389 m²; AWATER: 23,258,499 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 Cass County?

Cass County, Nebraska has 556.9 square miles (1,442.4 km²) of land and 8.98 square miles of water, for a total area of 565.9 square miles. It ranks #1862 of 3,222 U.S. county equivalents by land area.

Is Cass County the largest county in Nebraska?

No. Cass County ranks #67 of 93 in Nebraska by land area. The largest is Cherry County, with 5,960.1 square miles of land.

What counties border Cass County?

Cass County shares a land border with Otoe County, Sarpy County, Lancaster County, Mills County, Iowa, Fremont County, Iowa, and Saunders County.

What is the population of Cass County?

The Census Bureau estimates Cass County had 27,657 residents on July 1, 2025, ranking #1,565 of 3,222 county equivalents. That is 50 people per square mile of land.

What is the county seat of Cass County?

The county seat of Cass County is Plattsmouth.

What cities and towns are in Cass County?

Cass County has 15 incorporated places. The most populous five are Plattsmouth city, Louisville city, Eagle village, Weeping Water city, and Elmwood village; 13,504 residents live outside any incorporated place.

Is Cass County part of a metropolitan area?

Yes. It is an outlying county of the Omaha, NE-IA Metropolitan Statistical Area, which has 8 county equivalents and 1,009,836 residents.

How many ZIP codes are in Cass County?

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

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

It has less land than every state. Rhode Island, the smallest, has 1.9 times as much land.

How many acres of land are in Cass County?

The land measurement converts to approximately 356,423 acres. Including water, total area is approximately 362,170 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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