Niobrara County area

Niobrara County, Wyoming covers 2,627.9 square miles: 2,626 square miles of land and 1.919 square miles of water. Its county seat is Lusk. An estimated 2,341 people lived there in 2025.

Official Census measurements · GEOID 560272026 Gazetteer · retrieved September 27, 2026
Land area2,626 mi²
Water area1.919 mi²
Population (2025)2,341
People per mi²0.89

County outline

Generalized outline of Niobrara County, Wyoming
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 Niobrara County is located

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

Area breakdown

Land accounts for 99.9% of Niobrara County’s measured area and water for 0.1%. Its combined area converts to 6,806.4 square kilometers or approximately 1,681,886 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land2,626.0286,801.3811,680,657.9
Water1.9194.971,228.2
Total2,627.9476,806.3511,681,886.1

How Niobrara County compares

By original Census land area, Niobrara County ranks #16 of 23 in Wyoming and #203 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.657 times the Wyoming county-equivalent median of 3,996.8 square miles. It accounts for 2.7% of the combined county land area in the state.

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

Population and density of Niobrara County

The Census Bureau estimates that 2,341 people lived in Niobrara County on July 1, 2025. That ranks #3,090 of 3,222 county equivalents nationally and #23 of 23 in Wyoming. Since the April 1, 2020 estimates base of 2,468, the population has declined by 127 (−5.1%), compared with +2.1% for Wyoming as a whole.

With 2,626 square miles of land, that is 0.89 people per square mile (0.34 per km²), placing Niobrara County #3,166 nationally for density and #23 in Wyoming. The median county equivalent has 47 people per square mile; the Wyoming median is 4.1. Put another way, there are about 718 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate2,4512,4152,3412,3202,3152,341
Change—−36−74−21−5+26

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 Niobrara County

3 incorporated places lie at least partly in Niobrara County. Together they are home to 1,536 people (65.6%); the other 805 (34.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Lusk town, with 1,421 residents in the county.

Incorporated placePopulation 2025Since 2020Land mi²
Lusk townCounty seat1,421−7.5%2.068
Manville town91−2.2%0.272
Van Tassell town240%1.827

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

Metropolitan area

Niobrara County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

7 ZIP Code Tabulation Areas have land in Niobrara County; 4 of them have most of their land inside the county, and the others mainly cover neighboring areas.

82222822248222582227822428263382701

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 Niobrara County

Niobrara County shares a land border with 7 county equivalents, including 3 in South Dakota and Nebraska. It has more land than 6 of them. The largest neighbor is Converse County (4,255 mi²) and the smallest is Custer County (1,556.9 mi²). Together with its neighbors, Niobrara County forms a block of 18,949.7 mi² of land, of which it holds 13.9%.

Map of Niobrara County and the 7 county equivalents that border it Converse County, Wyoming: 4,255 mi² landWeston County, Wyoming: 2,398 mi² landFall River County, South Dakota: 1,739.9 mi² landGoshen County, Wyoming: 2,225.6 mi² landSioux County, Nebraska: 2,066.7 mi² landPlatte County, Wyoming: 2,081.5 mi² landCuster County, South Dakota: 1,556.9 mi² land
Niobrara 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. NiobraraCompare
Converse County4,2551.6× largerCompare
Weston County2,3981.1× smallerCompare
Goshen County2,225.61.2× smallerCompare
Platte County2,081.51.3× smallerCompare
Sioux CountyNebraska2,066.71.3× smallerCompare
Fall River CountySouth Dakota1,739.91.5× smallerCompare
Custer CountySouth Dakota1,556.91.7× smallerCompare

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

Niobrara County has more land than 2 of the 50 states. It is about 1.3 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.8 times as much land (4,842.5 mi²). Wyoming’s county land could hold about 37 areas the size of Niobrara County.

Land area: Niobrara County and the closest-sized states
Delaware1,948.6 mi²
Niobrara County2,626 mi²
Connecticut4,842.5 mi²

Another way to picture it: the same land area would fill a square about 51.2 miles (82.5 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 Niobrara County?

Niobrara County has more land than 3,019 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Niobrara County2,626 mi²
Wyoming median3,996.8 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 Niobrara County at #218 nationally by total area, 15 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 0.1%, compared with a national county-equivalent median of 1.2% — 1.1 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 Niobrara County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#202Yellowstone County, Montana2,633.4Compare
#203Niobrara County, Wyoming2,626This county
#204Gallatin County, Montana2,605.4Compare

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 43.062159, -104.468373. 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: 6,801,380,697 m²; AWATER: 4,969,450 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 Niobrara County?

Niobrara County, Wyoming has 2,626 square miles (6,801.4 km²) of land and 1.919 square miles of water, for a total area of 2,627.9 square miles. It ranks #203 of 3,222 U.S. county equivalents by land area.

Is Niobrara County the largest county in Wyoming?

No. Niobrara County ranks #16 of 23 in Wyoming by land area. The largest is Sweetwater County, with 10,427 square miles of land.

What counties border Niobrara County?

Niobrara County shares a land border with Converse County, Weston County, Fall River County, South Dakota, Goshen County, Sioux County, Nebraska, Platte County, and Custer County, South Dakota.

What is the population of Niobrara County?

The Census Bureau estimates Niobrara County had 2,341 residents on July 1, 2025, ranking #3,090 of 3,222 county equivalents. That is 0.89 people per square mile of land.

What is the county seat of Niobrara County?

The county seat of Niobrara County is Lusk.

What cities and towns are in Niobrara County?

Niobrara County has 3 incorporated places. The most populous are Lusk town, Manville town, and Van Tassell town; 805 residents live outside any incorporated place.

Is Niobrara County part of a metropolitan area?

No. Niobrara County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.

How many ZIP codes are in Niobrara County?

7 ZIP Code Tabulation Areas have land in Niobrara County, and 4 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

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

It has more land than 2 of the 50 states, including Delaware (1,948.6 square miles of land).

How many acres of land are in Niobrara County?

The land measurement converts to approximately 1,680,658 acres. Including water, total area is approximately 1,681,886 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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