Founded in Mar 1, 1808, Richland County is one of 88 counties in the state of Ohio. Historically, Richland County was formed from Fairfield County. The city of Mansfield is the county seat. With FIPS code of 139, Richland County has a population of 125,195 and area of 496.88 square miles (1,287 km2).
List of all cities in Richland County, OH alphabetically
| City/Town | Postal Code | Area Code |
| Adairo, OH | 44878 | 419/567 |
| Bellville, OH | 44813 | 419/567 |
| Bethlehem, OH | 44875 | 419/567 |
| Butler, OH | 44822 | 419/567 |
| Cool Ridge Heights, OH | 44905 | 419/567 |
| East Mansfield, OH | 44905 | 419/567 |
| Ganges, OH | 44875 | 419/567 |
| Lexington, OH | 44904 | 419/567 |
| Little London, OH | 44875 | 419/567 |
| Little Washington, OH | 44903 | 419/567 |
| Lucas, OH | 44843 | 419/567 |
| Mansfield, OH | 44901 | 419/567 |
| 44902 | 419/567 | |
| 44903 | 419/567 | |
| 44904 | 419/567 | |
| 44905 | 419/567 | |
| 44906 | 419/567 | |
| 44907 | 419/567 | |
| North Liberty, OH | 44822 | 419/567 |
| North Woodbury, OH | 44813 | 419/567 |
| Ontario, OH | 44862 | 419/567 |
| 44903 | 419/567 | |
| 44906 | 419/567 | |
| Pavonia, OH | 44903 | 419/567 |
| Sharon Township, OH | 44875 | 419/567 |
| Shelby, OH | 44875 | 419/567 |
| Shenadoah, OH | 44878 | 419/567 |
| Shiloh, OH | 44878 | 419/567 |
| Steam Corners, OH | 44904 | 419/567 |
| Taylortown, OH | 44875 | 419/567 |