| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sidney | 1 | 20,094 | 20,541 | -0.15% | 1,679 | 12 | City |
| Fort Loramie | 2 | 1,733 | 1,601 | -0.17% | 1,679 | 1 | Village |
| Anna | 3 | 1,565 | 1,471 | -0.06% | 1,412 | 1 | Village |
| Jackson Center | 4 | 1,446 | 1,439 | 0% | 840 | 2 | Village |
| Botkins | 5 | 1,132 | 1,156 | -0.09% | 896 | 1 | Village |
| Russia | 6 | 816 | 721 | 0.62% | 941 | 1 | Village |
| Port Jefferson | 7 | 336 | 315 | -0.59% | 2,211 | 0 | Village |
| Kettlersville | 8 | 174 | 166 | -1.14% | 169 | 1 | Village |
Sidney is the largest city in Shelby County, with a population of 20,094.
Kettlersville is the smallest city in Shelby County, with a population of 174.
There are 8 cities in Shelby County, Ohio.