Founded in 1822, Shiawassee County is one of 83 counties in the state of Michigan. Historically, Shiawassee County was formed from parts of Oakland County and St. Clair County. The city of Corunna is the county seat. With FIPS code of 155, Shiawassee County has a population of 67,877 and area of 541 square miles (1,401 km2).
List of all cities in Shiawassee County, MI alphabetically
| City/Town | Postal Code | Area Code |
| Bancroft, MI | 48414 | 989 |
| Byron, MI | 48418 | 810 |
| Corunna, MI | 48817 | 989 |
| Durand, MI | 48429 | 989 |
| Henderson, MI | 48841 | 989 |
| Laingsburg, MI | 48848 | 517 |
| Morrice, MI | 48857 | 517 |
| New Lothrop, MI | 48460 | 810 |
| Owosso, MI | 48841 | 989 |
| 48867 | 989 | |
| Perry, MI | 48872 | 517 |
| Shaftsburg, MI | 48882 | 517 |
| Vernon, MI | 48476 | 989 |
| Vernon City, MI | 48429 | 989 |