Founded in Apr 1, 1820, Marion County is one of 88 counties in the state of Ohio. Historically, Marion County was formed from Delaware County. The city of Marion is the county seat. With FIPS code of 101, Marion County has a population of 65,291 and area of 403.84 square miles (1,046 km2).
List of all cities in Marion County, OH alphabetically
| City/Town | Postal Code | Area Code |
| Caledonia, OH | 43314 | 419/567 |
| Fulfillment Corp of Amer Brm, OH | 43306 | 740 |
| Green Camp, OH | 43322 | 740 |
| La Rue, OH | 43332 | 740 |
| Marion, OH | 43301 | 740 |
| 43302 | 740 | |
| 43306 | 740 | |
| 43307 | 740 | |
| Martel, OH | 43335 | 419/567 |
| Morral, OH | 43337 | 740 |
| New Bloomington, OH | 43341 | 740 |
| Prospect, OH | 43342 | 740 |
| Readers Digest, OH | 43307 | 740 |
| Waldo, OH | 43356 | 740 |