The largest county in Wisconsin
There are two right answers. By land area it is Marathon County; by population it is Milwaukee 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 | Marathon County | 1,545 sq mi | 139,432 |
| 2 | Bayfield County | 1,478 sq mi | 16,787 |
| 3 | Marinette County | 1,399 sq mi | 42,574 |
| 4 | Douglas County | 1,304 sq mi | 43,990 |
| 5 | Sawyer County | 1,258 sq mi | 18,846 |
| 6 | Price County | 1,254 sq mi | 13,988 |
| 7 | Clark County | 1,210 sq mi | 35,052 |
| 8 | Dane County | 1,196 sq mi | 590,375 |
| 9 | Grant County | 1,148 sq mi | 52,446 |
| 10 | Oneida County | 1,114 sq mi | 38,131 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Milwaukee County | 924,216 | 3,828 per sq mi |
| 2 | Dane County | 590,375 | 493 per sq mi |
| 3 | Waukesha County | 417,210 | 759 per sq mi |
| 4 | Brown County | 275,803 | 520 per sq mi |
| 5 | Racine County | 198,919 | 598 per sq mi |
| 6 | Outagamie County | 195,894 | 307 per sq mi |
| 7 | Winnebago County | 174,218 | 401 per sq mi |
| 8 | Kenosha County | 168,448 | 620 per sq mi |
| 9 | Rock County | 166,472 | 232 per sq mi |
| 10 | Marathon County | 139,432 | 90.2 per sq mi |
And the smallest
More on Wisconsin
Rebuilt from source data 30 August 2026. How these figures are produced.