19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Huber Heights | 1 | 43,225 | 43,444 | -0.1% | 1,947 | 22.20 | City |
| Urbana township | 2 | 14,275 | 14,137 | 0.3% | 330 | 43.30 | Township |
| Urbana | 3 | 11,170 | 11,147 | 0.04% | 1,343 | 8.32 | City |
| Northridge | 4 | 7,701 | 7,318 | 0.12% | 2,514 | 3.06 | CDP |
| Johnson township | 5 | 3,144 | 3,122 | 0.26% | 104 | 30.09 | Township |
| Rush township | 6 | 2,813 | 2,791 | 0.29% | 89 | 31.69 | Township |
| Mad River township | 7 | 2,790 | 2,773 | 0.22% | 65 | 42.75 | Township |
| Union township | 8 | 2,113 | 2,098 | 0.24% | 56 | 37.71 | Township |
| St. Paris | 9 | 1,887 | 1,881 | 0.05% | 1,165 | 1.62 | Village |
| Mechanicsburg | 10 | 1,681 | 1,681 | 0% | 1,714 | 0.98 | Village |
| North Lewisburg | 11 | 1,649 | 1,639 | 0.12% | 1,535 | 1.07 | Village |
| Concord township | 12 | 1,415 | 1,403 | 0.28% | 47 | 30.09 | Township |
| Adams township | 13 | 1,018 | 1,012 | 0.1% | 33 | 31.05 | Township |
| Lawrenceville | 14 | 520 | 481 | 7.22% | 1,059 | 0.49 | CDP |
| Christiansburg | 15 | 497 | 507 | -0.4% | 2,088 | 0.24 | Village |
| Rosewood | 16 | 286 | 311 | 0.7% | 211 | 1.35 | CDP |
| Woodstock | 17 | 285 | 290 | -0.35% | 1,007 | 0.28 | Village |
| Brandt | 18 | 269 | 383 | 7.17% | 278 | 0.97 | CDP |
| Mutual | 19 | 127 | 127 | 0% | 941 | 0.14 | Village |
Huber Heights is the largest city in Champaign County, with a population of 43,225.
Mutual is the smallest city in Champaign County.
There are 19 cities in Champaign County, Ohio.