ZIP Codes of New Castle County, DE

Population & People
Population & People
Total Population
573,431
Household Income
Household Income
Median Income
$102,468
Housing
Housing
Total Housing Units
235,139
Business & Economy
Business & Economy
Total Businesses
17,786
Employment
Employment
Employment Rate
62.59%
Education
Education
Bachelor's Degree+
39.90%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 52 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:52 ZIP Codes (23 Standard, 12 PO Box, 17 Unique) [See All]
Area Code:302
Timezone:Eastern (GMT -05:00)
Local Time:2:11:36 PM
Population:573,431 [See All]
FIPS:10003
CBSA:Philadelphia-Camden-Wilmington, PA-NJ-DE-MD
Land Area:431 sq mi
Water Area:20 sq mi
Coordinates:39.7049, -75.6109
Quick Link:
https://www.zip-codes.com/county/de-new-castle.asp
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Delaware's largest county
573,431 residents — the most of 4 counties in Delaware.
Delaware's highest-income county
Average median income $102,468 — the highest of 4 counties.
Delaware's densest county
1,330 people per square mile.
Delaware's most-educated county
39.9% of adults 25+ have a bachelor's degree+.
Delaware's most foreign-born county
12.9% of residents are foreign-born.
Extreme geographic sprawl
The largest ZIP spans 1340× the smallest by area — 82.1 sq mi down to 0.06.

Standout ZIPs in this County


Most Populous
New Castle · 62,392 people
10.9% of county total
Highest Income
Hockessin · $172,696 median
1.7× county average
Largest Land Area
Middletown · 82.1 sq mi
Spans the most ground
Fastest Growth
Newark · 48.3% (10-yr)
4,070 → 6,036 residents
Most Educated
Wilmington · 78.5% bachelor's+
4,844 of 6,172 adults 25+

Things worth knowing about New Castle County


573,431 residents live across 52 ZIPs covering 431 sq mi, served by 17 distinct USPS-recognized cities.

Population moved from 540,805 to 573,431 from 2014 to 2024 — a +6.0% change. 22 ZIPs gained residents, 6 lost (and 1 held flat).

The county's wealthiest ZIP 19707 (Hockessin, $172,696 median) and poorest ZIP 19801 (Wilmington, $52,810) are 8.0 miles apart — a 3.3× income gap across local geography.

Median home values vary 4.8× across this county — from $194,600 in 19802 (Wilmington) to $936,900 in 19807 (Wilmington).

Density varies 548× across the county — from 180 people/sq mi in 19734 (Townsend) to 98,467 in 19717 (Newark).

Educational attainment ranges from 23.3% bachelor's+ in 19720 (New Castle) to 78.5% in 19807 (Wilmington) — the breadth of educational profiles across the area.

Within Delaware, this is the #1 most populous of 4 counties and ranks #1 for median household income with the #4 fastest decade growth .

Hosts 4 single-entity Unique ZIPs: 19884Bank Of America ; 19893Chase Manhattan Bank N A ; 19898Wilmington ; and 19895Delmarva Power .

Weighted by population, the typical household earns about $95,647 across the county — reflecting what a typical resident sees, not a simple ZIP average.

39.9% of adults age 25+ hold a bachelor's degree or higher (159,354 of 399,404 reporting). The most-educated ZIPs cluster around Wilmington.

23 Standard delivery, 12 PO Box only, 17 single-entity Unique ZIPs serve this county.

Stories about New Castle County


Higher-education hub

4 ZIPs in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.

Wilmington
78.5%
7,815 residents
Wilmington
70.7%
9,777 residents
Hockessin
64.4%
17,376 residents
Wilmington
60.9%
22,279 residents

Single-entity addresses

17 ZIP codes in this county serve a single facility — typically theme parks, universities, large corporations, airports, or government complexes.

Chase Manhattan Bank N A
non-residential
Wilmington
non-residential
Delmarva Power
non-residential
Wilmington
non-residential
Shared Firm Zip
non-residential
Bank Of America
non-residential
Shared Firm Zip
non-residential
Bank Of America
non-residential
Wilmington Trust
non-residential
Shared Firm Zip
non-residential
Shared Firm Zip
non-residential
Shared Firm Zip
non-residential
New Castle
non-residential
Christiana Medical Center
non-residential
Shared Firm Zip
non-residential
Shared Firm Zip
non-residential
Astrazeneca
non-residential

Two counties in one

Median household income spans 3.3× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Hockessin
Median income: $172,696
Population: 17,376
Bachelor's+: 64.4%
vs
Poorest ZIP (pop >= 500)
Wilmington
Median income: $52,810
Population: 16,327
Bachelor's+: 29.3%
For every $1 of household income in 19801, the typical household in 19707 earns $3.27.

All ZIP Codes in New Castle County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
19720New CastleStandard62,392$75,40350.13.1%
19702NewarkStandard55,683$92,44628.26.0%
19709MiddletownStandard53,234$132,95682.140.7%
19711NewarkStandard49,432$95,40327.7-2.5%
19701BearStandard42,984$111,19827.75.4%
19805WilmingtonStandard41,402$60,2215.30.8%
19808WilmingtonStandard39,082$94,23413.82.0%
19713NewarkStandard30,747$76,49312.60.3%
19810WilmingtonStandard26,530$112,7757.93.5%
19802WilmingtonStandard26,051$53,8124.02.7%
19803WilmingtonStandard22,279$135,21812.64.9%
19804WilmingtonStandard18,779$79,7017.74.4%
19707HockessinStandard17,376$172,69612.89.3%
19801WilmingtonStandard16,327$52,8105.92.7%
19703ClaymontStandard15,460$76,9397.22.1%
19809WilmingtonStandard14,311$81,28810.7-1.1%
19734TownsendStandard14,214$127,80379.122.6%
19806WilmingtonStandard9,777$88,8551.50.9%
19807WilmingtonStandard7,815$153,34118.99.9%
19717NewarkStandard6,0360.148.3%
19706Delaware CityPO Box2,038$83,6817.31.3%
19731Port PennPO Box655$71,2823.5254.1%
19730OdessaPO Box425$112,0830.6-40.9%
19733Saint GeorgesPO Box186$82,6040.1-37.8%
19736YorklynStandard1270.6
19732RocklandPO Box89$236,0001.521.9%
19710MontchaninPO Box00.5-100.0%
19735WinterthurStandard00.4
19716NewarkStandard00.9-100.0%
19893WilmingtonUnique0.0
19898WilmingtonUnique0.0
19895WilmingtonUnique0.0
19892WilmingtonUnique0.0
19886WilmingtonUnique0.0
19891WilmingtonUnique0.0
19880WilmingtonPO Box0.0
19885WilmingtonUnique0.0
19884WilmingtonUnique0.0
19890WilmingtonUnique0.0
19708KirkwoodPO Box0.0
19726New CastleUnique0.0
19715NewarkPO Box0.0
19714NewarkPO Box0.0
19725NewarkUnique0.0
19712NewarkUnique0.0
19721New CastleUnique0.0
19718NewarkUnique0.0
19896WilmingtonUnique0.0
19894WilmingtonUnique0.0
19897WilmingtonUnique0.0
19899WilmingtonPO Box0.0
19850WilmingtonPO Box0.0

Adjacent & Nearby Counties