29 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 19720 | New Castle | 60,593 |
| 19702 | Newark | 56,049 |
| 19709 | Middletown | 50,542 |
| 19711 | Newark | 49,113 |
| 19701 | Bear | 44,801 |
| 19805 | Wilmington | 40,315 |
| 19808 | Wilmington | 38,334 |
| 19713 | Newark | 30,549 |
| 19810 | Wilmington | 25,859 |
| 19802 | Wilmington | 25,670 |
| 19803 | Wilmington | 21,971 |
| 19804 | Wilmington | 18,231 |
| 19707 | Hockessin | 17,366 |
| 19801 | Wilmington | 16,170 |
| 19703 | Claymont | 15,936 |
| 19809 | Wilmington | 15,129 |
| 19734 | Townsend | 14,151 |
| 19806 | Wilmington | 9,934 |
| 19807 | Wilmington | 7,763 |
| 19717 | Newark | 6,522 |
| 19706 | Delaware City | 2,059 |
| 19731 | Port Penn | 630 |
| 19730 | Odessa | 506 |
| 19733 | Saint Georges | 182 |
| 19732 | Rockland | 155 |
| 19736 | Yorklyn | 13 |
| 19735 | Winterthur | 0 |
| 19710 | Montchanin | 0 |
| 19716 | Newark | 0 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 29 ZCTAs in New Castle County, Delaware (US Census).