21 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 48060 | Port Huron | 39,342 |
| 48059 | Fort Gratiot | 15,499 |
| 48079 | Saint Clair | 12,711 |
| 48001 | Algonac | 11,224 |
| 48040 | Marysville | 9,925 |
| 48074 | Smiths Creek | 9,624 |
| 48039 | Marine City | 7,437 |
| 48054 | East China | 7,188 |
| 48049 | North Street | 5,468 |
| 48097 | Yale | 5,418 |
| 48023 | Fair Haven | 5,031 |
| 48041 | Memphis | 4,302 |
| 48014 | Capac | 4,294 |
| 48063 | Columbus | 4,206 |
| 48064 | Casco | 4,180 |
| 48006 | Avoca | 3,889 |
| 48027 | Goodells | 3,187 |
| 48002 | Allenton | 3,120 |
| 48022 | Emmett | 2,530 |
| 48032 | Jeddo | 1,871 |
| 48028 | Harsens Island | 1,272 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 21 ZCTAs in St. Clair County, Michigan (US Census).