15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Huber Heights | 1 | 43,626 | 43,444 | 0.08% | 1,925 | 23 | City |
| Urbana | 2 | 14,208 | 14,138 | 0.11% | 328 | 43 | Township |
| Urbana | 3 | 11,217 | 11,184 | 0.05% | 1,349 | 8 | City |
| Johnson | 4 | 3,153 | 3,139 | 0.1% | 105 | 30 | Township |
| Rush | 5 | 2,808 | 2,792 | 0.07% | 89 | 32 | Township |
| Mad River | 6 | 2,779 | 2,767 | 0.11% | 65 | 43 | Township |
| Union | 7 | 2,119 | 2,096 | 0.24% | 56 | 38 | Township |
| St. Paris | 8 | 1,886 | 1,883 | 0% | 1,164 | 2 | Village |
| Mechanicsburg | 9 | 1,681 | 1,679 | 0% | 1,714 | 1 | Village |
| North Lewisburg | 10 | 1,658 | 1,640 | 0.18% | 1,544 | 1 | Village |
| Concord | 11 | 1,396 | 1,391 | 0.14% | 46 | 30 | Township |
| Adams | 12 | 1,018 | 1,008 | 0.3% | 33 | 31 | Township |
| Christiansburg | 13 | 502 | 506 | -0.2% | 2,109 | 0 | Village |
| Woodstock | 14 | 290 | 294 | -0.34% | 1,025 | 0 | Village |
| Mutual | 15 | 126 | 126 | 0% | 933 | 0 | Village |
Huber Heights is the largest city in Champaign County, with a population of 43,626.
Mutual is the smallest city in Champaign County, with a population of 126.
There are 15 cities in Champaign County, Ohio.