County outline
Where Dickinson County is located
Area breakdown
Land accounts for 94.2% of Dickinson County’s measured area and water for 5.8%. Its combined area converts to 1,046.3 square kilometers or approximately 258,536 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 380.548 | 985.615 | 243,550.7 |
| Water | 23.414 | 60.642 | 14,985 |
| Total | 403.962 | 1,046.257 | 258,535.7 |
How Dickinson County compares
By original Census land area, Dickinson County ranks #99 of 99 in Iowa and #2601 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.668 times the Iowa county-equivalent median of 569.6 square miles. It accounts for 0.7% of the combined county land area in the state.
See the complete Iowa ranking · What counts as a county equivalent?
Population and density of Dickinson County
The Census Bureau estimates that 18,077 people lived in Dickinson County on July 1, 2025. That ranks #1,995 of 3,222 county equivalents nationally and #39 of 99 in Iowa. Since the April 1, 2020 estimates base of 17,710, the population has grown by 367 (+2.1%), compared with +1.5% for Iowa as a whole.
With 380.5 square miles of land, that is 48 people per square mile (18 per km²), placing Dickinson County #1,605 nationally for density and #24 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 13 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 17,775 | 17,885 | 18,056 | 18,081 | 18,072 | 18,077 |
| Change | — | +110 | +171 | +25 | −9 | +5 |
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 Dickinson County
10 incorporated places lie at least partly in Dickinson County. Together they are home to 13,318 people (73.7%); the other 4,759 (26.3%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Spirit Lake city, with 5,525 residents in the county. Among places with at least 1,000 residents in 2020, Arnolds Park city grew fastest since then (+7.4%).
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Spirit Lake cityCounty seat | 5,525 | +1.5% | 4.511 |
| Milford city | 3,209 | −3.5% | 2.296 |
| Arnolds Park city | 1,198 | +7.4% | 1.789 |
| Lake Park city | 1,111 | −5% | 1.579 |
| Okoboji city | 712 | −6.6% | 1.753 |
| Orleans city | 493 | −5.2% | 1.138 |
| Wahpeton city | 333 | −3.5% | 1.198 |
| West Okoboji city | 309 | +1.3% | 1.253 |
| Terril city | 304 | −9.3% | 0.543 |
| Superior city | 124 | −6.8% | 0.429 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Dickinson County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Dickinson County is a central county of the Spirit Lake, IA Micropolitan Statistical Area. Dickinson County is the area’s only county equivalent, so the micro area has the same 380.5 square miles of land. By combined land it ranks #501 of 542 micropolitan areas, and #529 by population. It belongs to the Spencer-Spirit Lake, IA Combined Statistical Area.
ZIP codes
10 ZIP Code Tabulation Areas have land in Dickinson County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.
51331513345133851345513475135151355513605136351364
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 Dickinson County
Dickinson County shares a land border with 4 county equivalents, including 1 in Minnesota. Each of them has more land than Dickinson County. The largest neighbor is Jackson County (703 mi²) and the smallest is Emmet County (395.9 mi²). Together with its neighbors, Dickinson County forms a block of 2,445.3 mi² of land, of which it holds 15.6%.
| Bordering county equivalent | Land mi² | Size vs. Dickinson | Compare |
|---|---|---|---|
| Jackson CountyMinnesota | 703 | 1.8× larger | Compare |
| Clay County | 567.2 | 1.5× larger | Compare |
| Osceola County | 398.7 | about the same | Compare |
| Emmet County | 395.9 | about the same | Compare |
How big is Dickinson County compared with U.S. states?
Dickinson County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.7 times as much. Iowa’s county land could hold about 147 areas the size of Dickinson County.
Another way to picture it: the same land area would fill a square about 19.5 miles (31.4 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 Dickinson County?
Dickinson County has more land than 621 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 Dickinson County at #2,585 nationally by total area, 16 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.
Its water share is 5.8%, compared with a national county-equivalent median of 1.2% — 4.6 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 Dickinson County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #2600 | Jefferson County, Kentucky | 380.8 | Compare |
| #2601 | Dickinson County, Iowa | 380.5 | This county |
| #2602 | Bond County, Illinois | 380.3 | 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 43.389611, -95.196057. 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: 985,613,775 m²; AWATER: 60,641,191 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 Dickinson County?
Dickinson County, Iowa has 380.5 square miles (985.6 km²) of land and 23.4 square miles of water, for a total area of 404 square miles. It ranks #2601 of 3,222 U.S. county equivalents by land area.
Is Dickinson County the largest county in Iowa?
No. Dickinson County ranks #99 of 99 in Iowa by land area. The largest is Kossuth County, with 972.7 square miles of land.
What counties border Dickinson County?
Dickinson County shares a land border with Clay County, Jackson County, Minnesota, Emmet County, and Osceola County.
What is the population of Dickinson County?
The Census Bureau estimates Dickinson County had 18,077 residents on July 1, 2025, ranking #1,995 of 3,222 county equivalents. That is 48 people per square mile of land.
What is the county seat of Dickinson County?
The county seat of Dickinson County is Spirit Lake.
What cities and towns are in Dickinson County?
Dickinson County has 10 incorporated places. The most populous five are Spirit Lake city, Milford city, Arnolds Park city, Lake Park city, and Okoboji city; 4,759 residents live outside any incorporated place.
Is Dickinson County part of a metropolitan area?
Yes. It is a central county of the Spirit Lake, IA Micropolitan Statistical Area.
How many ZIP codes are in Dickinson County?
10 ZIP Code Tabulation Areas have land in Dickinson County, and 7 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Dickinson County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 2.7 times as much land.
How many acres of land are in Dickinson County?
The land measurement converts to approximately 243,551 acres. Including water, total area is approximately 258,536 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.