44 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 21234 | Parkville | 65,010 |
| 21117 | Owings Mills | 61,337 |
| 21222 | Dundalk | 58,935 |
| 21207 | Gwynn Oak | 49,599 |
| 21228 | Catonsville | 49,417 |
| 21221 | Essex | 43,536 |
| 21220 | Middle River | 42,936 |
| 21236 | Nottingham | 39,653 |
| 21244 | Windsor Mill | 39,545 |
| 21093 | Lutherville Timonium | 38,895 |
| 21208 | Pikesville | 38,108 |
| 21227 | Halethorpe | 35,695 |
| 21136 | Reisterstown | 33,778 |
| 21133 | Randallstown | 31,847 |
| 21237 | Rosedale | 30,851 |
| 21209 | Baltimore | 30,766 |
| 21030 | Cockeysville | 25,312 |
| 21286 | Towson | 21,782 |
| 21204 | Towson | 19,605 |
| 21128 | Perry Hall | 14,954 |
| 21219 | Sparrows Point | 9,873 |
| 21120 | Parkton | 7,286 |
| 21131 | Phoenix | 7,050 |
| 21163 | Woodstock | 7,031 |
| 21152 | Sparks Glencoe | 6,402 |
| 21013 | Baldwin | 5,985 |
| 21087 | Kingsville | 5,742 |
| 21111 | Monkton | 4,690 |
| 21252 | Towson | 4,675 |
| 21162 | White Marsh | 4,511 |
| 21057 | Glen Arm | 4,463 |
| 21155 | Upperco | 3,124 |
| 21053 | Freeland | 3,018 |
| 21250 | Baltimore | 3,001 |
| 21082 | Hydes | 525 |
| 21153 | Stevenson | 519 |
| 21071 | Glyndon | 355 |
| 21156 | Upper Falls | 297 |
| 21052 | Fort Howard | 246 |
| 21051 | Fork | 132 |
| 21023 | Butler | 83 |
| 21105 | Maryland Line | 31 |
| 21031 | Hunt Valley | 25 |
| 21285 | Towson | 3 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 44 ZCTAs in Baltimore County, Maryland (US Census).