The largest county in Kansas
There are two right answers. By land area it is Butler County; by population it is Johnson County. Which one you want depends on what you meant by largest.
Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.
By land area
| Rank | Name | Land area | Population |
|---|---|---|---|
| 1 | Butler County | 1,430 sq mi | 69,484 |
| 2 | Finney County | 1,302 sq mi | 37,505 |
| 3 | Reno County | 1,255 sq mi | 61,539 |
| 4 | Sumner County | 1,182 sq mi | 22,312 |
| 5 | Greenwood County | 1,143 sq mi | 5,826 |
| 6 | Barber County | 1,134 sq mi | 4,083 |
| 7 | Cowley County | 1,126 sq mi | 34,382 |
| 8 | Ford County | 1,098 sq mi | 33,993 |
| 9 | Ness County | 1,075 sq mi | 2,617 |
| 10 | Thomas County | 1,075 sq mi | 7,725 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Johnson County | 636,906 | 1,345 per sq mi |
| 2 | Sedgwick County | 538,433 | 540 per sq mi |
| 3 | Shawnee County | 178,607 | 328 per sq mi |
| 4 | Wyandotte County | 170,597 | 1,125 per sq mi |
| 5 | Douglas County | 120,920 | 265 per sq mi |
| 6 | Leavenworth County | 84,590 | 183 per sq mi |
| 7 | Riley County | 72,598 | 119 per sq mi |
| 8 | Butler County | 69,484 | 48.6 per sq mi |
| 9 | Reno County | 61,539 | 49.0 per sq mi |
| 10 | Saline County | 53,377 | 74.1 per sq mi |
And the smallest
More on Kansas
Rebuilt from source data 30 August 2026. How these figures are produced.