State · counties
Counties in Maryland
The 24 counties recorded for ZIP codes in Maryland, with the number of ZIP codes, total population, and median income in each. County names come from the site's ZIP records (GeoNames postal data); population is summed across member ZIPs and median income is the equal-weight average of member ZIP medians, the same rollup rule described on the methodology page.
| County | ZIP codes | Population | Median income |
|---|---|---|---|
| Montgomery | 76 | 1,067,856 | $145,803 |
| Prince George's | 64 | 948,337 | $101,706 |
| Baltimore | 53 | 822,939 | $106,635 |
| Anne Arundel | 43 | 603,449 | $126,607 |
| Baltimore (city) | 39 | 595,553 | $65,839 |
| Howard | 22 | 317,377 | $169,331 |
| Frederick | 31 | 284,907 | $122,138 |
| Harford | 21 | 259,995 | $111,182 |
| Carroll | 13 | 176,976 | $118,864 |
| Charles | 24 | 161,546 | $122,980 |
| Washington | 23 | 154,302 | $78,875 |
| St. Mary's | 29 | 117,774 | $127,136 |
| Cecil | 17 | 103,876 | $88,631 |
| Wicomico | 18 | 102,596 | $80,364 |
| Calvert | 14 | 95,344 | $132,924 |
| Allegany | 22 | 70,459 | $55,753 |
| Worcester | 12 | 55,738 | $78,538 |
| Queen Anne's | 13 | 45,705 | $99,798 |
| Talbot | 15 | 37,287 | $100,600 |
| Caroline | 11 | 34,631 | $66,458 |
| Dorchester | 16 | 30,879 | $68,904 |
| Garrett | 9 | 26,558 | $65,595 |
| Kent | 9 | 24,194 | $82,078 |
| Somerset | 11 | 22,980 | $63,419 |
Total population across listed counties: 6,161,258.