County ZIP codes · Maryland · FIPS 24021
Frederick County, MD ZIP Codes
Frederick County, Maryland has 39 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 35 residential and 4 for PO boxes or a single organization. 28 of the residential ones lie mainly in Frederick County and 7 mainly in a neighboring county; 11 cross the county line. Median household income ranges from $65,809 in 21719 (Cascade) to $204,013 in 20842 (Dickerson) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Frederick County?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
How different are its ZIP codes?
The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $100,750 and $161,063.
They carry 31 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 35 residential ZIP codes in Frederick County
28 ZIP codes lie mainly in Frederick County; 7 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 21702 | Frederick | 49,605 | 1,189 | $107k | $426k | 100% |
| 21701 | Frederick | 43,048 | 1,084 | $107k | $435k | 100% |
| 21703 | Frederick | 41,960 | 1,310 | $106k | $385k | 100% |
| 21771 | Mount Airy | 33,031 | 369 | $157k | $556k | 51% |
| 21704 | Frederick | 20,006 | 751 | $161k | $612k | 100% |
| 21774 | New Market | 17,134 | 1,210 | $171k | $541k | 100% |
| 21769 | Middletown | 11,965 | 298 | $152k | $507k | 99% |
| 21788 | Thurmont | 11,654 | 178 | $99k | $379k | 100% |
| 21793 | Walkersville | 10,719 | 502 | $122k | $459k | 100% |
| 21770 | Monrovia | 8,751 | 764 | $184k | $633k | 100% |
| 21754 | Ijamsville | 8,156 | 374 | $182k | $647k | 100% |
| 21716 | Brunswick | 7,200 | 2,636 | $109k | $361k | 100% |
| 21727 | Emmitsburg | 6,052 | 193 | $95k | $331k | 100% |
| 21755 | Jefferson | 5,909 | 172 | $137k | $530k | 100% |
| 21773 | Myersville | 5,826 | 161 | $162k | $544k | 100% |
| 21791 | Union Bridge | 5,340 | 116 | $93k | $380k | 61% |
| 21710 | Adamstown | 4,661 | 159 | $164k | $591k | 100% |
| 21758 | Knoxville | 4,409 | 138 | $112k | $425k | 50% |
| 21798 | Woodsboro | 2,928 | 180 | $117k | $498k | 100% |
| 21777 | Point Of Rocks | 2,462 | 2,242 | $160k | $481k | 100% |
| 21780 | Sabillasville | 2,159 | 98 | $84k | $452k | 96% |
| 21778 | Rocky Ridge | 745 | 41 | $77k | $382k | 100% |
| 21717 | Buckeystown | 245 | 404 | $158k | $431k | 100% |
| 21790 | Tuscarora | 170 | 36 | $78k | – | 100% |
| 21762 | Libertytown | 139 | 311 | – | – | 100% |
| 21718 | Burkittsville | 134 | 404 | $94k | $576k | 100% |
| 21714 | Braddock Heights | 95 | 213 | $162k | $416k | 100% |
| 21705 | Frederick | 6 | 250 | – | – | 100% |
Partly in Frederick County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 21757 | Keymar | 2,671 | 76 | $101k | $466k | 48% |
| 21783 | Smithsburg | 9,910 | 208 | $101k | $340k | 27% |
| 20842 | Dickerson | 2,369 | 43 | $204k | $746k | 23% |
| 21776 | New Windsor | 6,261 | 177 | $133k | $462k | 21% |
| 21787 | Taneytown | 11,645 | 191 | $92k | $355k | 13% |
| 20871 | Clarksburg | 30,182 | 1,319 | $178k | $669k | 6% |
| 21719 | Cascade | 1,178 | 285 | $66k | $214k | 3% |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).
Which ZIP codes cross the county line?
12 ZIP codes of Frederick County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Frederick | Elsewhere |
|---|---|---|
| 21771 | 51% | Carroll County 26%; Howard County 18%; Montgomery County 4% |
| 20871 | 6% | Montgomery County 94% |
| 21769 | 99% | |
| 21787 | 13% | Carroll County 87% |
| 21783 | 27% | Washington County 73% |
| 21776 | 21% | Carroll County 79% |
| 21791 | 61% | Carroll County 39% |
| 21758 | 50% | Washington County 50% |
| 21757 | 48% | Carroll County 52% |
| 20842 | 23% | Montgomery County 77% |
| 21780 | 96% | Washington County 4% |
| 21719 | 3% | Washington County 97% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
PO Box and single-organization ZIP codes
| ZIP | Postal name |
|---|---|
| 21709 | Frederick |
| 21759 | Ladiesburg |
| 21775 | New Midway |
| 21792 | Unionville |
Source: GeoNames postal codes (CC BY 4.0).
Which first three digits do Frederick County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Frederick County's ZIP codes use 2 prefixes: 208 and 217.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.