Frederick County ZIP Codes
Frederick County is a county of Maryland.
- ZIP codes
- 31
- Cities & towns
- 26
- Area codes
- 6
- Land area
- 661 sq mi
Every ZIP code in Frederick County
| ZIP code | City |
|---|---|
| 21701 | Frederick |
| 21702 | Frederick |
| 21703 | Frederick |
| 21704 | Frederick |
| 21705 | Frederick |
| 21709 | Frederick |
| 21710 | Adamstown |
| 21714 | Braddock Heights |
| 21716 | Brunswick |
| 21717 | Buckeystown |
| 21718 | Burkittsville |
| 21727 | Emmitsburg |
| 21754 | Ijamsville |
| 21755 | Jefferson |
| 21758 | Knoxville |
| 21759 | Ladiesburg |
| 21762 | Libertytown |
| 21769 | Middletown |
| 21770 | Monrovia |
| 21771 | Mount Airy |
| 21773 | Myersville |
| 21774 | New Market |
| 21775 | New Midway |
| 21777 | Point Of Rocks |
| 21778 | Rocky Ridge |
| 21780 | Sabillasville |
| 21788 | Thurmont |
| 21790 | Tuscarora |
| 21792 | Unionville |
| 21793 | Walkersville |
| 21798 | Woodsboro |
We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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 Frederick County codes above are listed without a column we would have to invent.
Cities and towns in Frederick County
A further 15 places in Frederick 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 Frederick County
Telephone and postal boundaries are drawn by different bodies, so these codes overlap the county without matching its edges.
- 227 Area code 227
- 240 Area code 240
- 301 Area code 301
- 410 Area code 410
- 443 Area code 443
- 667 Area code 667
Where Frederick 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 Frederick 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.