County outline
Where Johnston County is located
Area breakdown
Land accounts for 97.7% of Johnston County’s measured area and water for 2.3%. Its combined area converts to 1,705.1 square kilometers or approximately 421,348 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 643.05 | 1,665.492 | 411,552 |
| Water | 15.307 | 39.645 | 9,796.5 |
| Total | 658.357 | 1,705.137 | 421,348.5 |
How Johnston County compares
By original Census land area, Johnston County ranks #57 of 77 in Oklahoma and #1480 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.801 times the Oklahoma county-equivalent median of 802.7 square miles. It accounts for 0.9% of the combined county land area in the state.
See the complete Oklahoma ranking · What counts as a county equivalent?
Population and density of Johnston County
The Census Bureau estimates that 10,448 people lived in Johnston County on July 1, 2025. That ranks #2,454 of 3,222 county equivalents nationally and #57 of 77 in Oklahoma. Since the April 1, 2020 estimates base of 10,274, the population has grown by 174 (+1.7%), compared with +4.1% for Oklahoma as a whole.
With 643.1 square miles of land, that is 16 people per square mile (6.3 per km²), placing Johnston County #2,432 nationally for density and #52 in Oklahoma. The median county equivalent has 47 people per square mile; the Oklahoma median is 28. Put another way, there are about 39 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 10,242 | 10,318 | 10,311 | 10,233 | 10,325 | 10,448 |
| Change | — | +76 | −7 | −78 | +92 | +123 |
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 Johnston County
7 incorporated places lie at least partly in Johnston County. Together they are home to 5,392 people (51.6%); the other 5,056 (48.4%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Tishomingo city, with 3,123 residents in the county.
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Tishomingo cityCounty seat | 3,123 | +0.5% | 5.276 |
| Mannsville town | 753 | +3.4% | 3.035 |
| Ravia town | 472 | +1.5% | 0.585 |
| Wapanucka town | 397 | +2.6% | 0.662 |
| Mill Creek town | 296 | +1.4% | 0.384 |
| Milburn town | 253 | +1.2% | 0.469 |
| Bromide townAlso in 1 other county | 98 | +2.1% | 0.673 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Johnston County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Johnston 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
13 ZIP Code Tabulation Areas have land in Johnston County; 9 of them have most of their land inside the county, and the others mainly cover neighboring areas.
73086734017343273447734507345573460734617453074748748367485674871
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 Johnston County
Johnston County shares a land border with 7 county equivalents. It has more land than 3 of them. The largest neighbor is Atoka County (975.5 mi²) and the smallest is Marshall County (371.5 mi²). Together with its neighbors, Johnston County forms a block of 5,370.1 mi² of land, of which it holds 12%.
| Bordering county equivalent | Land mi² | Size vs. Johnston | Compare |
|---|---|---|---|
| Atoka County | 975.5 | 1.5× larger | Compare |
| Bryan County | 904.3 | 1.4× larger | Compare |
| Carter County | 822.3 | 1.3× larger | Compare |
| Pontotoc County | 720.4 | 1.1× larger | Compare |
| Coal County | 516.8 | 1.2× smaller | Compare |
| Murray County | 416.4 | 1.5× smaller | Compare |
| Marshall County | 371.5 | 1.7× smaller | Compare |
How big is Johnston County compared with U.S. states?
Johnston County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.6 times as much. Oklahoma’s county land could hold about 107 areas the size of Johnston County.
Another way to picture it: the same land area would fill a square about 25.4 miles (40.8 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 Johnston County?
Johnston County has more land than 1,742 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 Johnston County at #1,544 nationally by total area, 64 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 2.3%, compared with a national county-equivalent median of 1.2% — 1.2 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 Johnston County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1479 | Montgomery County, Kansas | 643.6 | Compare |
| #1480 | Johnston County, Oklahoma | 643.1 | This county |
| #1481 | Wayne County, Georgia | 641.8 | 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 34.313455, -96.654254. 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: 1,665,492,475 m²; AWATER: 39,645,103 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 Johnston County?
Johnston County, Oklahoma has 643.1 square miles (1,665.5 km²) of land and 15.3 square miles of water, for a total area of 658.4 square miles. It ranks #1480 of 3,222 U.S. county equivalents by land area.
Is Johnston County the largest county in Oklahoma?
No. Johnston County ranks #57 of 77 in Oklahoma by land area. The largest is Osage County, with 2,246.7 square miles of land.
What counties border Johnston County?
Johnston County shares a land border with Marshall County, Atoka County, Murray County, Pontotoc County, Coal County, Carter County, and Bryan County.
What is the population of Johnston County?
The Census Bureau estimates Johnston County had 10,448 residents on July 1, 2025, ranking #2,454 of 3,222 county equivalents. That is 16 people per square mile of land.
What is the county seat of Johnston County?
The county seat of Johnston County is Tishomingo.
What cities and towns are in Johnston County?
Johnston County has 7 incorporated places. The most populous five are Tishomingo city, Mannsville town, Ravia town, Wapanucka town, and Mill Creek town; 5,056 residents live outside any incorporated place.
Is Johnston County part of a metropolitan area?
No. Johnston County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Johnston County?
13 ZIP Code Tabulation Areas have land in Johnston 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 Johnston County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.6 times as much land.
How many acres of land are in Johnston County?
The land measurement converts to approximately 411,552 acres. Including water, total area is approximately 421,348 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.