Founded in 1831, Ionia County is one of 83 counties in the state of Michigan. Historically, Ionia County was formed from part of Mackinac County and unorganized territory. The city of Ionia is the county seat. With FIPS code of 67, Ionia County has a population of 67,197 and area of 580 square miles (1,502 km2).
List of all cities in Ionia County, MI alphabetically
| City/Town | Postal Code | Area Code |
| Belding, MI | 48809 | 616 |
| 48887 | 616 | |
| Clarksville, MI | 48815 | 616 |
| Hubbardston, MI | 48845 | 989 |
| Ionia, MI | 48846 | 616 |
| Lake Odessa, MI | 48849 | 616 |
| Lyons, MI | 48851 | 989 |
| Muir, MI | 48860 | 989 |
| Orleans, MI | 48865 | 616 |
| Palo, MI | 48870 | 989 |
| Pewamo, MI | 48873 | 989 |
| Portland, MI | 48875 | 517 |
| Saranac, MI | 48881 | 616 |
| Smyrna, MI | 48887 | 616 |