County · Delaware · United States
New Castle County ZIP codes
29 ZIP codes · 16 cities · FIPS 10003
Key facts
- State
- Delaware (DE)
- FIPS code
- 10003
- Population
- 573,030
- Median household income
- $89,901
- Median age
- 39.2
- Land area
- 426.3 sq mi (1,104.2 km²)
- Population density
- 1,344 / sq mi
- Area codes
- 302
Cities and ZIP codes in New Castle County (16)
About this page
County figures are Census county-level values (ACS 5-year); the ZIP list shows the ZIPs whose primary county this is — a ZIP on a border can also serve neighbouring counties.
Sources: U.S. Census Bureau (2020 county relationship file, ACS 5-year) · GeoNames. Methodology.