29 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 19720 | New Castle | 62,392 |
| 19702 | Newark | 55,683 |
| 19709 | Middletown | 53,234 |
| 19711 | Newark | 49,432 |
| 19701 | Bear | 42,984 |
| 19805 | Wilmington | 41,402 |
| 19808 | Wilmington | 39,082 |
| 19713 | Newark | 30,747 |
| 19810 | Wilmington | 26,530 |
| 19802 | Wilmington | 26,051 |
| 19803 | Wilmington | 22,279 |
| 19804 | Wilmington | 18,779 |
| 19707 | Hockessin | 17,376 |
| 19801 | Wilmington | 16,327 |
| 19703 | Claymont | 15,460 |
| 19809 | Wilmington | 14,311 |
| 19734 | Townsend | 14,214 |
| 19806 | Wilmington | 9,777 |
| 19807 | Wilmington | 7,815 |
| 19717 | Newark | 6,036 |
| 19706 | Delaware City | 2,038 |
| 19731 | Port Penn | 655 |
| 19730 | Odessa | 425 |
| 19733 | Saint Georges | 186 |
| 19736 | Yorklyn | 127 |
| 19732 | Rockland | 89 |
| 19735 | Winterthur | 0 |
| 19710 | Montchanin | 0 |
| 19716 | Newark | 0 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 29 ZCTAs in New Castle County, Delaware (US Census).