22 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wausau | 1 | 40,372 | 40,042 | 0.14% | 2,100 | 19 | City |
| Weston | 2 | 15,932 | 15,733 | 0.21% | 737 | 22 | Village |
| Kronenwetter | 3 | 8,466 | 8,372 | 0.19% | 164 | 52 | Village |
| Rib Mountain | 4 | 7,262 | 7,301 | 16.98% | 296 | 25 | Village |
| Rib Mountain | 5 | 7,262 | 7,301 | -0.08% | 296 | 25 | Village |
| Rib Mountain | 6 | 6,245 | 7,301 | 0.6% | 255 | 25 | Village |
| Rib Mountain | 7 | 6,245 | 7,301 | -14.08% | 255 | 25 | Village |
| Rothschild | 8 | 5,665 | 5,557 | 0.32% | 868 | 7 | Village |
| Mosinee | 9 | 4,567 | 4,459 | 0.4% | 581 | 8 | City |
| Maine | 10 | 2,618 | 2,606 | 0.08% | 61 | 43 | Village |
| Schofield | 11 | 2,359 | 2,154 | 1.46% | 1,115 | 2 | City |
| Spencer | 12 | 1,807 | 1,825 | -0.17% | 917 | 2 | Village |
| Stratford | 13 | 1,629 | 1,584 | 0.49% | 307 | 5 | Village |
| Marathon City | 14 | 1,537 | 1,578 | -0.45% | 471 | 3 | Village |
| Edgar | 15 | 1,423 | 1,443 | -0.21% | 787 | 2 | Village |
| Athens | 16 | 1,063 | 1,065 | 0% | 434 | 2 | Village |
| Hatley | 17 | 657 | 651 | 0.15% | 673 | 1 | Village |
| Unity | 18 | 375 | 387 | -0.53% | 378 | 1 | Village |
| Aniwa | 19 | 228 | 245 | -1.3% | 107 | 2 | Village |
| Eland | 20 | 185 | 196 | -1.07% | 84 | 2 | Village |
| Elderon | 21 | 154 | 162 | -0.65% | 137 | 1 | Village |
| Fenwood | 22 | 135 | 140 | -0.74% | 137 | 1 | Village |
Wausau is the largest city in Marathon County, with a population of 40,372.
Fenwood is the smallest city in Marathon County, with a population of 135.
There are 22 cities in Marathon County, Wisconsin.