23 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wausau | 1 | 39,928 | 40,027 | -0.05% | 2,077 | 19 | City |
| Weston | 2 | 16,125 | 15,734 | 0.49% | 746 | 22 | Village |
| Kronenwetter | 3 | 8,653 | 8,368 | 0.66% | 168 | 52 | Village |
| Rib Mountain | 4 | 6,278 | 5,963 | 0.66% | 521 | 12 | CDP |
| Rothschild | 5 | 5,484 | 5,559 | -0.27% | 840 | 7 | Village |
| Mosinee | 6 | 4,570 | 4,489 | 0.35% | 582 | 8 | City |
| Maine | 7 | 2,615 | 2,617 | 0% | 61 | 43 | Village |
| Schofield | 8 | 2,153 | 2,155 | 0% | 1,018 | 2 | City |
| Spencer | 9 | 1,805 | 1,822 | -0.17% | 916 | 2 | Village |
| Stratford | 10 | 1,581 | 1,580 | 0% | 298 | 5 | Village |
| Marathon City | 11 | 1,547 | 1,579 | -0.39% | 474 | 3 | Village |
| Edgar | 12 | 1,447 | 1,439 | 0.14% | 800 | 2 | Village |
| Athens | 13 | 1,072 | 1,064 | 0.19% | 438 | 2 | Village |
| Hatley | 14 | 692 | 646 | 1.32% | 709 | 1 | Village |
| Unity | 15 | 371 | 385 | -0.8% | 374 | 1 | Village |
| Aniwa | 16 | 243 | 243 | 0% | 114 | 2 | Village |
| Eland | 17 | 197 | 197 | 0% | 89 | 2 | Village |
| Elderon | 18 | 154 | 161 | -0.65% | 137 | 1 | Village |
| Fenwood | 19 | 137 | 141 | -0.72% | 139 | 1 | Village |
| Whittlesey | 20 | 93 | 122 | 0% | 83 | 1 | CDP |
| Paac Ciinak | 21 | 82 | 75 | 6.49% | 82 | 1 | CDP |
| Chelsea | 22 | 72 | 89 | -2.7% | 156 | 0 | CDP |
| Knowlton | 23 | 47 | 78 | -9.62% | 47 | 1 | CDP |
Wausau is the largest city in Marathon County, with a population of 39,928.
Knowlton is the smallest city in Marathon County, with a population of 47.
There are 23 cities in Marathon County, Wisconsin.