County ZIP codes · Maryland · FIPS 24013
Carroll County, MD ZIP Codes
Carroll County, Maryland has 16 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 15 residential and 1 for PO boxes or a single organization. 9 of the residential ones lie mainly in Carroll County and 6 mainly in a neighboring county; 12 cross the county line. Median household income ranges from $91,682 in 21787 (Taneytown) to $191,804 in 21104 (Marriottsville) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Carroll 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 $104,966 and $135,069.
They carry 14 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 15 residential ZIP codes in Carroll County
9 ZIP codes lie mainly in Carroll County; 6 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 21784 | Sykesville | 39,258 | 699 | $139k | $492k | 82% |
| 21157 | Westminster | 38,984 | 502 | $105k | $424k | 100% |
| 21158 | Westminster | 22,083 | 301 | $110k | $385k | 100% |
| 21074 | Hampstead | 14,777 | 392 | $109k | $378k | 72% |
| 21102 | Manchester | 12,162 | 299 | $135k | $393k | 77% |
| 21787 | Taneytown | 11,645 | 191 | $92k | $355k | 87% |
| 21048 | Finksburg | 10,481 | 385 | $132k | $459k | 100% |
| 21776 | New Windsor | 6,261 | 177 | $133k | $462k | 79% |
| 21757 | Keymar | 2,671 | 76 | $101k | $466k | 52% |
Partly in Carroll County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 21791 | Union Bridge | 5,340 | 116 | $93k | $380k | 39% |
| 21104 | Marriottsville | 6,052 | 355 | $192k | $680k | 32% |
| 21797 | Woodbine | 8,643 | 198 | $189k | $736k | 32% |
| 21771 | Mount Airy | 33,031 | 369 | $157k | $556k | 26% |
| 21155 | Upperco | 3,313 | 150 | $123k | $480k | 11% |
| 21136 | Reisterstown | 32,088 | 571 | $119k | $422k | 4% |
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 Carroll County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Carroll | Elsewhere |
|---|---|---|
| 21784 | 82% | Howard County 18% |
| 21771 | 26% | Frederick County 51%; Howard County 18%; Montgomery County 4% |
| 21136 | 4% | Baltimore County 96% |
| 21074 | 72% | Baltimore County 28% |
| 21102 | 77% | Baltimore County 23% |
| 21787 | 87% | Frederick County 13% |
| 21797 | 32% | Howard County 67%; Montgomery County 1% |
| 21776 | 79% | Frederick County 21% |
| 21104 | 32% | Howard County 53%; Baltimore County 15% |
| 21791 | 39% | Frederick County 61% |
| 21155 | 11% | Baltimore County 89% |
| 21757 | 52% | Frederick County 48% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
PO Box and single-organization ZIP codes
| ZIP | Postal name |
|---|---|
| 21088 | Lineboro |
Source: GeoNames postal codes (CC BY 4.0).
Which first three digits do Carroll County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Carroll County's ZIP codes use 3 prefixes: 210, 211 and 217.
| Prefix | Sectional center | Here | All codes |
|---|---|---|---|
| 210 | Linthicum, MD (SCF 210) | 3 | 58 |
| 211 | Linthicum, MD (SCF 210) | 6 | 34 |
| 217 | Baltimore, MD (SCF 212) | 7 | 66 |
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.