County outline
Where Treasure County is located
Area breakdown
Land accounts for 99.3% of Treasure County’s measured area and water for 0.7%. Its combined area converts to 2,549.6 square kilometers or approximately 630,031 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 977.801 | 2,532.493 | 625,792.6 |
| Water | 6.622 | 17.151 | 4,238.1 |
| Total | 984.423 | 2,549.644 | 630,030.7 |
How Treasure County compares
By original Census land area, Treasure County ranks #53 of 56 in Montana and #709 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.414 times the Montana county-equivalent median of 2,363.3 square miles. It accounts for 0.7% of the combined county land area in the state.
See the complete Montana ranking · What counts as a county equivalent?
Population and density of Treasure County
The Census Bureau estimates that 728 people lived in Treasure County on July 1, 2025. That ranks #3,201 of 3,222 county equivalents nationally and #55 of 56 in Montana. Since the April 1, 2020 estimates base of 760, the population has declined by 32 (−4.2%), compared with +5.6% for Montana as a whole.
With 977.8 square miles of land, that is 0.74 people per square mile (0.29 per km²), placing Treasure County #3,176 nationally for density and #49 in Montana. The median county equivalent has 47 people per square mile; the Montana median is 2.8. Put another way, there are about 860 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 758 | 770 | 754 | 771 | 735 | 728 |
| Change | — | +12 | −16 | +17 | −36 | −7 |
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 Treasure County
1 incorporated place lies at least partly in Treasure County. Together they are home to 262 people (36%); the other 466 (64%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Hysham town, with 262 residents in the county.
Metropolitan area
Treasure 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
3 ZIP Code Tabulation Areas have land in Treasure County, and each lies mostly inside the county.
590105903859076
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering Treasure County
Treasure County shares a land border with 3 county equivalents. Each of them has more land than Treasure County. The largest neighbor is Rosebud County (5,008.1 mi²) and the smallest is Yellowstone County (2,633.4 mi²). Together with its neighbors, Treasure County forms a block of 13,617.1 mi² of land, of which it holds 7.2%.
| Bordering county equivalent | Land mi² | Size vs. Treasure | Compare |
|---|---|---|---|
| Rosebud County | 5,008.1 | 5.1× larger | Compare |
| Big Horn County | 4,997.8 | 5.1× larger | Compare |
| Yellowstone County | 2,633.4 | 2.7× larger | Compare |
How big is Treasure County compared with U.S. states?
Treasure County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.1 times as much. Montana’s county land could hold about 149 areas the size of Treasure County.
Another way to picture it: the same land area would fill a square about 31.3 miles (50.3 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 Treasure County?
Treasure County has more land than 2,513 of the other 3,221 county equivalents in the dataset.
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 Treasure County at #796 nationally by total area, 87 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 0.7%, compared with a national county-equivalent median of 1.2% — 0.5 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 Treasure County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #708 | Meade County, Kansas | 978.1 | Compare |
| #709 | Treasure County, Montana | 977.8 | This county |
| #710 | Marengo County, Alabama | 976.9 | Compare |
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 46.227113, -107.275296. 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: 2,532,492,088 m²; AWATER: 17,149,960 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Treasure County?
Treasure County, Montana has 977.8 square miles (2,532.5 km²) of land and 6.622 square miles of water, for a total area of 984.4 square miles. It ranks #709 of 3,222 U.S. county equivalents by land area.
Is Treasure County the largest county in Montana?
No. Treasure County ranks #53 of 56 in Montana by land area. The largest is Beaverhead County, with 5,542.7 square miles of land.
What counties border Treasure County?
Treasure County shares a land border with Rosebud County, Yellowstone County, and Big Horn County.
What is the population of Treasure County?
The Census Bureau estimates Treasure County had 728 residents on July 1, 2025, ranking #3,201 of 3,222 county equivalents. That is 0.74 people per square mile of land.
What is the county seat of Treasure County?
The county seat of Treasure County is Hysham.
Is Treasure County part of a metropolitan area?
No. Treasure County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Treasure County?
3 ZIP Code Tabulation Areas have land in Treasure County, and 3 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Treasure County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.1 times as much land.
How many acres of land are in Treasure County?
The land measurement converts to approximately 625,793 acres. Including water, total area is approximately 630,031 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.