Roger Mills County area

Roger Mills County, Oklahoma covers 1,146.4 square miles: 1,141.1 square miles of land and 5.285 square miles of water. Its county seat is Cheyenne. An estimated 3,259 people lived there in 2025.

Official Census measurements · GEOID 401292026 Gazetteer · retrieved September 27, 2026
Land area1,141.1 mi²
Water area5.285 mi²
Population (2025)3,259
People per mi²2.9

County outline

Generalized outline of Roger Mills County, Oklahoma
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 Roger Mills County is located

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

Area breakdown

Land accounts for 99.5% of Roger Mills County’s measured area and water for 0.5%. Its combined area converts to 2,969.2 square kilometers or approximately 733,709 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land1,141.1352,955.526730,326.4
Water5.28513.6883,382.4
Total1,146.422,969.214733,708.8

How Roger Mills County compares

By original Census land area, Roger Mills County ranks #13 of 77 in Oklahoma and #545 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.422 times the Oklahoma county-equivalent median of 802.7 square miles. It accounts for 1.7% of the combined county land area in the state.

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

Population and density of Roger Mills County

The Census Bureau estimates that 3,259 people lived in Roger Mills County on July 1, 2025. That ranks #3,015 of 3,222 county equivalents nationally and #74 of 77 in Oklahoma. Since the April 1, 2020 estimates base of 3,442, the population has declined by 183 (−5.3%), compared with +4.1% for Oklahoma as a whole.

With 1,141.1 square miles of land, that is 2.9 people per square mile (1.1 per km²), placing Roger Mills County #2,994 nationally for density and #75 in Oklahoma. The median county equivalent has 47 people per square mile; the Oklahoma median is 28. Put another way, there are about 224 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate3,4313,3673,3643,3193,2873,259
Change—−64−3−45−32−28

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 Roger Mills County

5 incorporated places lie at least partly in Roger Mills County. Together they are home to 1,345 people (41.3%); the other 1,914 (58.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Cheyenne town, with 725 residents in the county. By land, Sweetwater town is the largest at 15.9 mi² across all its counties.

Incorporated placePopulation 2025Since 2020Land mi²
Cheyenne townCounty seat725−5.8%0.988
Hammon townAlso in 1 other county440−4.6%0.732
Reydon town130−5.8%0.493
Strong City town31−3.1%0.498
Sweetwater townAlso in 1 other county19−5%15.9

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

Metropolitan area

Roger Mills 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

9 ZIP Code Tabulation Areas have land in Roger Mills County; 6 of them have most of their land inside the county, and the others mainly cover neighboring areas.

736287363873642736447365073654736607366273666

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 Roger Mills County

Roger Mills County shares a land border with 6 county equivalents, including 2 in Texas. It has more land than 5 of them. The largest neighbor is Ellis County (1,231.5 mi²) and the smallest is Beckham County (901.7 mi²). Together with its neighbors, Roger Mills County forms a block of 7,083.5 mi² of land, of which it holds 16.1%.

Map of Roger Mills County and the 6 county equivalents that border it Ellis County, Oklahoma: 1,231.5 mi² landBeckham County, Oklahoma: 901.7 mi² landCuster County, Oklahoma: 988.8 mi² landHemphill County, Texas: 906.3 mi² landWheeler County, Texas: 914.5 mi² landDewey County, Oklahoma: 999.6 mi² land
Roger Mills 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. Roger MillsCompare
Ellis County1,231.51.1× largerCompare
Dewey County999.61.1× smallerCompare
Custer County988.81.2× smallerCompare
Wheeler CountyTexas914.51.2× smallerCompare
Hemphill CountyTexas906.31.3× smallerCompare
Beckham County901.71.3× smallerCompare

How big is Roger Mills County compared with U.S. states?

Roger Mills County has more land than 1 of the 50 states. It is about 1.1 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.7 times as much land (1,948.6 mi²). Oklahoma’s county land could hold about 60 areas the size of Roger Mills County.

Land area: Roger Mills County and the closest-sized states
Rhode Island1,033.9 mi²
Roger Mills County1,141.1 mi²
Delaware1,948.6 mi²

Another way to picture it: the same land area would fill a square about 33.8 miles (54.4 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 Roger Mills County?

Roger Mills County has more land than 2,677 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Roger Mills County1,141.1 mi²
Oklahoma median802.7 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 Roger Mills County at #630 nationally by total area, 85 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 0.5%, compared with a national county-equivalent median of 1.2% — 0.7 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 Roger Mills County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#544Cowlitz County, Washington1,141.2Compare
#545Roger Mills County, Oklahoma1,141.1This county
#546McMullen County, Texas1,139.8Compare

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 35.708554, -99.741572. 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: 2,955,524,823 m²; AWATER: 13,688,537 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 Roger Mills County?

Roger Mills County, Oklahoma has 1,141.1 square miles (2,955.5 km²) of land and 5.285 square miles of water, for a total area of 1,146.4 square miles. It ranks #545 of 3,222 U.S. county equivalents by land area.

Is Roger Mills County the largest county in Oklahoma?

No. Roger Mills County ranks #13 of 77 in Oklahoma by land area. The largest is Osage County, with 2,246.7 square miles of land.

What counties border Roger Mills County?

Roger Mills County shares a land border with Ellis County, Beckham County, Custer County, Hemphill County, Texas, Wheeler County, Texas, and Dewey County.

What is the population of Roger Mills County?

The Census Bureau estimates Roger Mills County had 3,259 residents on July 1, 2025, ranking #3,015 of 3,222 county equivalents. That is 2.9 people per square mile of land.

What is the county seat of Roger Mills County?

The county seat of Roger Mills County is Cheyenne.

What cities and towns are in Roger Mills County?

Roger Mills County has 5 incorporated places. The most populous are Cheyenne town, Hammon town, Reydon town, Strong City town, and Sweetwater town; 1,914 residents live outside any incorporated place.

Is Roger Mills County part of a metropolitan area?

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

How many ZIP codes are in Roger Mills County?

9 ZIP Code Tabulation Areas have land in Roger Mills County, and 6 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does Roger Mills County compare with U.S. states?

It has more land than 1 of the 50 states, including Rhode Island (1,033.9 square miles of land).

How many acres of land are in Roger Mills County?

The land measurement converts to approximately 730,326 acres. Including water, total area is approximately 733,709 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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