New Castle County, Delaware
New Castle County is a county in Delaware. Its county FIPS code is 10003. Use the boundary map and neighboring areas below to check the jurisdiction you need.
- Official code
- 10003
- Representative coordinates
- 39.575915, -75.644132
- County type
- County
- County seat or government
- Wilmington
- Resident population, July 2025
- 588,026
- Land area
- 1,104.211 km²
- Water area
- 175.313 km²
- State
- Delaware
The representative point identifies this area. It is not a street address or a boundary survey.
Time zones in New Castle County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| America/New_York | UTC-05:00 in January; UTC-04:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Listed zones overlap the mapped area. A point lookup can distinguish sides of a boundary. Your device’s zone may differ.
Census ZIP areas
19701 · 19702 · 19703 · 19706 · 19707 · 19709 · 19710 · 19711 · 19713 · 19716 · 19717 · 19720 · 19730 · 19731 · 19732 · 19733 · 19734 · 19735 · 19736 · 19801 · 19802 · 19803 · 19804 · 19805 · 19806 · 19807 · 19808 · 19809 · 19810 · 19938 · 19977 · 21912
These statistical areas overlap the boundary. They are not delivery assignments; confirm mailing details with USPS ZIP Code Lookup.
Official county information
Use the US government local-office directory ↗ to find the office responsible for your address. A county website has not been confidently matched here. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Cities, towns and communities
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
- Arden village, DE
- Ardencroft village, DE
- Ardentown village, DE
- Bear CDP, DE
- Bellefonte town, DE
- Brookside CDP, DE
- Claymont CDP, DE
- Clayton town, DE
- Delaware City city, DE
- Edgemoor CDP, DE
- Elsmere town, DE
- Glasgow CDP, DE
- Greenville CDP, DE
- Hockessin CDP, DE
- Middletown town, DE
- Newark city, DE
- New Castle city, DE
- Newport town, DE
- North Star CDP, DE
- Odessa town, DE
- Pike Creek CDP, DE
- Pike Creek Valley CDP, DE
- Port Penn CDP, DE
- St. Georges CDP, DE
- Smyrna town, DE
- Townsend town, DE
- Wilmington city, DE
- Wilmington Manor CDP, DE
Areas sharing the mapped boundary
These areas touch this mapped boundary.
Before using this answer on a form
Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.
Find the county at your current point, check its ZIP area, or find its physical time zone.