Founded in 1811, St. Mary Parish is one of 64 parishes in the state of Louisiana. Historically, St. Mary Parish was formed from part of St. Martin Parish. The city of Franklin is the parish seat. With FIPS code of 101, St. Mary Parish has a population of 48,232 and area of 612 square miles (1,585 km2).
List of all cities in Saint Mary Parish, LA alphabetically
| City/Town | Postal Code | Area Code |
| Amelia, LA | 70340 | 985 |
| Baldwin, LA | 70514 | 337 |
| Bayou Vista, LA | 70380 | 985 |
| Berwick, LA | 70342 | 985 |
| Calumet, LA | 70392 | 985 |
| Centerville, LA | 70522 | 337 |
| Charenton, LA | 70523 | 337 |
| Cypremort Point, LA | 70538 | 337 |
| Franklin, LA | 70538 | 337 |
| Garden City, LA | 70540 | 337 |
| Glenwild, LA | 70342 | 985 |
| Idlewild, LA | 70392 | 985 |
| Morgan City, LA | 70380 | 985 |
| 70381 | 985 | |
| Patterson, LA | 70392 | 985 |