26 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 20653 | Lexington Park | 27,053 |
| 20659 | Mechanicsville | 23,346 |
| 20650 | Leonardtown | 15,522 |
| 20619 | California | 13,925 |
| 20636 | Hollywood | 11,089 |
| 20634 | Great Mills | 7,853 |
| 20670 | Patuxent River | 1,403 |
| 20620 | Callaway | 1,325 |
| 20609 | Avenue | 1,240 |
| 20618 | Bushwood | 1,087 |
| 20624 | Clements | 990 |
| 20686 | Saint Marys City | 963 |
| 20690 | Tall Timbers | 843 |
| 20674 | Piney Point | 807 |
| 20621 | Chaptico | 775 |
| 20692 | Valley Lee | 721 |
| 20628 | Dameron | 631 |
| 20684 | Saint Inigoes | 627 |
| 20680 | Ridge | 588 |
| 20687 | Scotland | 360 |
| 20630 | Drayden | 307 |
| 20606 | Abell | 247 |
| 20626 | Coltons Point | 239 |
| 20656 | Loveville | 203 |
| 20667 | Park Hall | 159 |
| 20660 | Morganza | 0 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 26 ZCTAs in St. Mary's County, Maryland (US Census).