County facts · Land area · October 21, 2026
Largest Counties in Iowa by Area and Population
The largest Iowa counties by land area and by 2023 population, plus the smallest, county seats and a link to each official parcel map.
Looking for the largest counties in Iowa? Iowa has 99 counties covering about 55,853 square miles of land, based on the Census Bureau's 2020 Gazetteer. The largest by land area is Kossuth County, at about 973 square miles, roughly 2.6 times the size of the smallest, Dickinson County (381 sq mi). Measured by people instead, the largest is Polk County, with about 505,255 residents in the Census Bureau's July 1, 2023 estimate.
Each table below links the county's Platbookmapper page and its official parcel viewer, so you can go straight from the numbers to the property lines.
Iowa counties at a glance
- Counties: 99
- Land area: about 55,853 sq mi, plus about 419 sq mi of water inside county lines
- Residents, 2023 estimates: about 3,207,004, or about 57 people per square mile of land
- Median county land area: about 570 sq mi
- With a verified public parcel viewer in our directory: 98 of 99
The 10 largest Iowa counties by land area
| # | County | Seat | Land (sq mi) | 2023 pop. | People per sq mi | Parcel viewer |
|---|---|---|---|---|---|---|
| 1 | Kossuth County | Algona | 973 | 14,396 | 15 | CAMAvision Maps |
| 2 | Pottawattamie County | Council Bluffs | 951 | 93,179 | 98 | ArcGIS Map Viewer |
| 3 | Woodbury County | Sioux City | 873 | 105,951 | 121 | Beacon (Schneider Geospatial) |
| 4 | Plymouth County | Le Mars | 863 | 25,722 | 30 | Beacon (Schneider Geospatial) |
| 5 | Clayton County | Elkader | 778 | 16,969 | 22 | Beacon (Schneider Geospatial) |
| 6 | Sioux County | Orange City | 768 | 36,246 | 47 | Beacon (Schneider Geospatial) |
| 7 | Fayette County | West Union | 731 | 19,210 | 26 | Beacon (Schneider Geospatial) |
| 8 | Jasper County | Newton | 730 | 37,919 | 52 | Beacon (Schneider Geospatial) |
| 9 | Tama County | Toledo | 721 | 16,833 | 23 | CAMAvision Maps |
| 10 | Linn County | Cedar Rapids | 717 | 228,972 | 319 | county web map |
Together these 10 cover about 15% of Iowa's land area and hold about 19% of its residents.
The 10 most populous Iowa counties
| # | County | Seat | 2023 pop. | Land (sq mi) | Parcel viewer |
|---|---|---|---|---|---|
| 1 | Polk County | Des Moines | 505,255 | 572 | listed link under review |
| 2 | Linn County | Cedar Rapids | 228,972 | 717 | county web map |
| 3 | Scott County | Davenport | 174,270 | 458 | Beacon (Schneider Geospatial) |
| 4 | Johnson County | Iowa City | 157,528 | 613 | Beacon (Schneider Geospatial) |
| 5 | Black Hawk County | Waterloo | 130,471 | 566 | Beacon (Schneider Geospatial) |
| 6 | Dallas County | Adel | 111,092 | 588 | county web map |
| 7 | Woodbury County | Sioux City | 105,951 | 873 | Beacon (Schneider Geospatial) |
| 8 | Dubuque County | Dubuque | 98,887 | 608 | Beacon (Schneider Geospatial) |
| 9 | Story County | Nevada | 98,566 | 573 | Beacon (Schneider Geospatial) |
| 10 | Pottawattamie County | Council Bluffs | 93,179 | 951 | ArcGIS Map Viewer |
These 10 hold about 53% of Iowa's residents in the 2023 estimates.
The 5 smallest Iowa counties by land area
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Dickinson County | Spirit Lake | 381 | 18,056 | Beacon (Schneider Geospatial) |
| Emmet County | Estherville | 396 | 9,229 | Beacon (Schneider Geospatial) |
| Osceola County | Sibley | 399 | 5,978 | Beacon (Schneider Geospatial) |
| Worth County | Northwood | 400 | 7,297 | Beacon (Schneider Geospatial) |
| Winnebago County | Forest City | 400 | 10,571 | Beacon (Schneider Geospatial) |
Most and least crowded
- Most people per square mile: Polk County, about 883 (then Scott County, 380, and Linn County, 319)
- Fewest people per square mile: Adams County, about 8.4 (then Ringgold County, 8.7, and Taylor County, 11)
Counties with the most water
The Census Bureau reports water separately from land. It counts lakes, reservoirs, rivers and, for coastal and Great Lakes counties, the water inside the county boundary.
- Dickinson County: about 23 sq mi of water, 6% of its total area
- Lee County: about 21 sq mi of water, 4% of its total area
- Allamakee County: about 20 sq mi of water, 3% of its total area
Using these numbers in a land search
- Land area is not parcel count. A large rural county can hold fewer parcels than a small suburban one, so size alone says little about how busy its parcel map is.
- Search, don't scroll. In a big county, type an address, owner name or parcel number into the viewer's search box, where it has one, instead of panning across the map.
- Records follow the county line. Deeds, plats and tax bills are kept by the county where the parcel sits, so a tract that crosses a county line usually has a parcel number in each county.
- Rounded figures. Land and water areas are rounded to whole square miles. People per square mile is the 2023 estimate divided by land area.
Related guides
- Iowa county GIS websites by viewer
- Iowa landowner maps for hunting
- Illinois–Iowa border counties
- Iowa–Minnesota border counties
- Iowa–Missouri border counties
- Iowa–Nebraska border counties
More: All Iowa counties on Platbookmapper
Sources
- U.S. Census Bureau Gazetteer files, 2020 county land and water area.
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2023 (July 1, 2023 estimates)
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 21, 2026) for each county's official parcel viewer.
- County seats: Wikidata (county seat property), cross-checked against Census place names.