20 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mansfield | 1 | 47,610 | 47,525 | 0.04% | 1,542 | 31 | City |
| Shelby | 2 | 9,225 | 9,289 | -0.14% | 1,462 | 6 | City |
| Sharon | 3 | 8,945 | 9,011 | -0.17% | 371 | 24 | Township |
| Butler | 4 | 8,293 | 8,275 | 0.25% | 533 | 16 | Township |
| Butler | 5 | 6,677 | 6,658 | 0.41% | 202 | 33 | Township |
| Ontario | 6 | 6,643 | 6,668 | -0.08% | 599 | 11 | City |
| Washington | 7 | 6,572 | 6,609 | -0.14% | 206 | 32 | Township |
| Mifflin | 8 | 6,085 | 6,110 | -0.11% | 276 | 22 | Township |
| Butler | 9 | 3,457 | 3,559 | -0.43% | 105 | 33 | Township |
| Worthington | 10 | 2,981 | 2,991 | -0.13% | 83 | 36 | Township |
| Bellville | 11 | 2,003 | 1,960 | 0.4% | 703 | 3 | Village |
| Weller | 12 | 1,877 | 1,883 | -0.05% | 77 | 24 | Township |
| Cass | 13 | 1,602 | 1,612 | -0.06% | 62 | 26 | Township |
| Butler | 14 | 1,434 | 1,447 | 0% | 41 | 35 | Township |
| Butler | 15 | 1,286 | 1,298 | -0.31% | 53 | 24 | Township |
| Bloominggrove | 16 | 1,285 | 1,291 | -0.16% | 51 | 25 | Township |
| Butler | 17 | 1,183 | 1,182 | -0.17% | 47 | 25 | Township |
| Butler | 18 | 936 | 943 | -0.21% | 726 | 1 | Village |
| Shiloh | 19 | 611 | 616 | -0.16% | 667 | 1 | Village |
| Lucas | 20 | 585 | 589 | -0.17% | 864 | 1 | Village |
Mansfield is the largest city in Richland County, with a population of 47,610.
Lucas is the smallest city in Richland County, with a population of 585.
There are 20 cities in Richland County, Ohio.