County outline
Where Adair County is located
Area breakdown
Land accounts for 99.8% of Adair County’s measured area and water for 0.2%. Its combined area converts to 1,477 square kilometers or approximately 364,975 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 569.271 | 1,474.405 | 364,333.4 |
| Water | 1.003 | 2.598 | 641.9 |
| Total | 570.274 | 1,477.003 | 364,975.4 |
How Adair County compares
By original Census land area, Adair County ranks #53 of 99 in Iowa and #1787 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.999 times the Iowa county-equivalent median of 569.6 square miles. It accounts for 1% of the combined county land area in the state.
See the complete Iowa ranking · What counts as a county equivalent?
Population and density of Adair County
The Census Bureau estimates that 7,403 people lived in Adair County on July 1, 2025. That ranks #2,702 of 3,222 county equivalents nationally and #88 of 99 in Iowa. Since the April 1, 2020 estimates base of 7,502, the population has declined by 99 (−1.3%), compared with +1.5% for Iowa as a whole.
With 569.3 square miles of land, that is 13 people per square mile (5 per km²), placing Adair County #2,537 nationally for density and #91 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 49 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 7,498 | 7,529 | 7,466 | 7,418 | 7,465 | 7,403 |
| Change | — | +31 | −63 | −48 | +47 | −62 |
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 Adair County
7 incorporated places lie at least partly in Adair County. Together they are home to 4,757 people (64.3%); the other 2,646 (35.7%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Greenfield city, with 2,070 residents in the county. By land, Stuart city is the largest at 2.879 mi² across all its counties.
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Greenfield cityCounty seat | 2,070 | +0.1% | 1.801 |
| Adair cityAlso in 1 other county | 758 | −2.3% | 2.215 |
| Stuart cityAlso in 1 other county | 747 | +3.6% | 2.879 |
| Fontanelle city | 673 | −2.3% | 0.857 |
| Orient city | 352 | −3.3% | 0.435 |
| Bridgewater city | 141 | −3.4% | 0.288 |
| Casey cityAlso in 1 other county | 16 | 0% | 0.739 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Adair County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Adair 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
14 ZIP Code Tabulation Areas have land in Adair County; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.
5000250020500485007050155501645025050273508015083750846508495085850859
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 Adair County
Adair County shares a land border with 5 county equivalents. It has more land than 4 of them. The largest neighbor is Guthrie County (590.6 mi²) and the smallest is Adams County (423.4 mi²). Together with its neighbors, Adair County forms a block of 3,132.2 mi² of land, of which it holds 18.2%.
| Bordering county equivalent | Land mi² | Size vs. Adair | Compare |
|---|---|---|---|
| Guthrie County | 590.6 | about the same | Compare |
| Cass County | 564.3 | about the same | Compare |
| Madison County | 561 | about the same | Compare |
| Union County | 423.6 | 1.3× smaller | Compare |
| Adams County | 423.4 | 1.3× smaller | Compare |
How big is Adair County compared with U.S. states?
Adair County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.8 times as much. Iowa’s county land could hold about 98 areas the size of Adair County.
Another way to picture it: the same land area would fill a square about 23.9 miles (38.4 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 Adair County?
Adair County has more land than 1,435 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 Adair County at #1,931 nationally by total area, 144 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 0.2%, compared with a national county-equivalent median of 1.2% — 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 Adair County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1786 | Hardin County, Iowa | 569.3 | Compare |
| #1787 | Adair County, Iowa | 569.3 | This county |
| #1788 | Howard County, Nebraska | 569.3 | 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 41.328528, -94.478164. 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: 1,474,404,194 m²; AWATER: 2,597,996 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 Adair County?
Adair County, Iowa has 569.3 square miles (1,474.4 km²) of land and 1.003 square miles of water, for a total area of 570.3 square miles. It ranks #1787 of 3,222 U.S. county equivalents by land area.
Is Adair County the largest county in Iowa?
No. Adair County ranks #53 of 99 in Iowa by land area. The largest is Kossuth County, with 972.7 square miles of land.
What counties border Adair County?
Adair County shares a land border with Cass County, Madison County, Guthrie County, Adams County, and Union County.
What is the population of Adair County?
The Census Bureau estimates Adair County had 7,403 residents on July 1, 2025, ranking #2,702 of 3,222 county equivalents. That is 13 people per square mile of land.
What is the county seat of Adair County?
The county seat of Adair County is Greenfield.
What cities and towns are in Adair County?
Adair County has 7 incorporated places. The most populous five are Greenfield city, Adair city, Stuart city, Fontanelle city, and Orient city; 2,646 residents live outside any incorporated place.
Is Adair County part of a metropolitan area?
No. Adair County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Adair County?
14 ZIP Code Tabulation Areas have land in Adair County, and 5 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Adair County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.8 times as much land.
How many acres of land are in Adair County?
The land measurement converts to approximately 364,333 acres. Including water, total area is approximately 364,975 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.