New Castle Delaware ZIP Codes

New Castle holds 3 ZIP codes, all inside one county and one postal prefix.

Every ZIP code in New Castle

The complete list of New Castle, Delaware ZIP codes with the county each falls in.
ZIP code	County
19720	New Castle County
19721	New Castle County
19726	New Castle County

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the New Castle codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for New Castle. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.

How these codes cluster

Every New Castle ZIP code begins 197. Those first three digits identify the sectional center facility that processes mail for this part of Delaware. Statewide that range covers 27 ZIP codes, so New Castle accounts for 11% of it.

Every Delaware ZIP prefix and the region it covers →

Area codes covering New Castle

ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The code below serves the same ground New Castle occupies.

302 Area code 302

New Castle Delaware area codes in full →

Where New Castle's ZIP codes sit

Each point is one New Castle ZIP code, plotted from its record coordinates. The outline is the convex envelope of those points — a footprint, not a boundary.

Reference points and footprint
Not an official NANPA boundary
Not a USPS delivery area

Cities near New Castle

The closest places to New Castle with their own ZIP code list, nearest first.
City	Distance	ZIP codes
Wilmington Delaware ZIP codes	4.9 mi	25 ZIP codes
Delaware City Delaware ZIP codes	6.8 mi	1 ZIP code
Bear Delaware ZIP codes	7.0 mi	1 ZIP code
Newark Delaware ZIP codes	10 mi	10 ZIP codes
Odessa Delaware ZIP codes	16 mi	1 ZIP code
Middletown Delaware ZIP codes	18 mi	1 ZIP code
Townsend Delaware ZIP codes	20 mi	1 ZIP code
Smyrna Delaware ZIP codes	26 mi	1 ZIP code

Straight-line distance between place reference points, not driving distance.