St. Mary's County ZIP Codes
St. Mary's County is a county of Maryland.
- ZIP codes
- 29
- Cities & towns
- 29
- Area codes
- 3
- Land area
- 359 sq mi
Every ZIP code in St. Mary's County
| ZIP code | City |
|---|---|
| 20606 | Abell |
| 20609 | Avenue |
| 20618 | Bushwood |
| 20619 | California |
| 20620 | Callaway |
| 20621 | Chaptico |
| 20622 | Charlotte Hall |
| 20624 | Clements |
| 20626 | Coltons Point |
| 20627 | Compton |
| 20628 | Dameron |
| 20630 | Drayden |
| 20634 | Great Mills |
| 20635 | Helen |
| 20636 | Hollywood |
| 20650 | Leonardtown |
| 20653 | Lexington Park |
| 20656 | Loveville |
| 20659 | Mechanicsville |
| 20660 | Morganza |
| 20667 | Park Hall |
| 20670 | Patuxent River |
| 20674 | Piney Point |
| 20680 | Ridge |
| 20684 | Saint Inigoes |
| 20686 | Saint Marys City |
| 20687 | Scotland |
| 20690 | Tall Timbers |
| 20692 | Valley Lee |
We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the St. Mary's County codes above are listed without a column we would have to invent.
Cities and towns in St. Mary's County
A further 28 places in St. Mary's County appear in the postal source without a page of its own; their codes are in the table above and each one links to its own page.
Area codes covering St. Mary's County
Telephone and postal boundaries are drawn by different bodies, so these codes overlap the county without matching its edges.
Where St. Mary's County's ZIP codes sit
- Reference points and footprint
- Not an official NANPA boundary
- Not a USPS delivery area
Scope every ZIP code recorded in St. Mary's County. Source GeoNames US postal codes (2026-07 postal dump), Census 2024 county Gazetteer (2024 Gazetteer) and geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot). Updated . The outline is a convex envelope of ZIP reference points, not a jurisdiction boundary.