15 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Huber Heights | 1 | 43,663 | 43,444 | 0.08% | 1,926 | 23 | City |
| Urbana | 2 | 14,224 | 14,138 | 0.11% | 328 | 43 | Township |
| Urbana | 3 | 11,224 | 11,184 | 0.06% | 1,350 | 8 | City |
| Johnson | 4 | 3,156 | 3,139 | 0.1% | 105 | 30 | Township |
| Rush | 5 | 2,810 | 2,792 | 0.07% | 89 | 32 | Township |
| Mad River | 6 | 2,782 | 2,767 | 0.11% | 65 | 43 | Township |
| Union | 7 | 2,124 | 2,096 | 0.24% | 56 | 38 | Township |
| St. Paris | 8 | 1,887 | 1,883 | 0.05% | 1,165 | 2 | Village |
| Mechanicsburg | 9 | 1,682 | 1,679 | 0.06% | 1,715 | 1 | Village |
| North Lewisburg | 10 | 1,662 | 1,640 | 0.24% | 1,547 | 1 | Village |
| Concord | 11 | 1,398 | 1,391 | 0.14% | 46 | 30 | Township |
| Adams | 12 | 1,021 | 1,008 | 0.29% | 33 | 31 | Township |
| Christiansburg | 13 | 501 | 506 | -0.2% | 2,105 | 0 | Village |
| Woodstock | 14 | 289 | 294 | -0.34% | 1,021 | 0 | Village |
| Mutual | 15 | 126 | 126 | 0% | 933 | 0 | Village |
Huber Heights is the largest city in Champaign County, with a population of 43,663.
Mutual is the smallest city in Champaign County, with a population of 126.
There are 15 cities in Champaign County, Ohio.