ZIP Codes of Delaware County, IA

Population & People
Population & People
Total Population
16,256
Household Income
Household Income
Median Income
$74,322
Housing
Housing
Total Housing Units
7,645
Business & Economy
Business & Economy
Total Businesses
459
Employment
Employment
Employment Rate
69.00%
Education
Education
Bachelor's Degree+
22.63%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 10 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:10 ZIP Codes (10 Standard, 0 PO Box, 0 Unique) [See All]
Area Codes:319 / 563
Timezone:Central (GMT -06:00)
Local Time:2:11:51 PM
Population:16,256 [See All]
FIPS:19055
Land Area:542 sq mi
Water Area:1 sq mi
Coordinates:42.4913, -91.3782
Quick Link:
https://www.zip-codes.com/county/ia-delaware.asp
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Extreme geographic sprawl
The largest ZIP spans 285× the smallest by area — 139.0 sq mi down to 0.49.
Striking education divide
Bachelor's share spans 8.7% to 38.9% — a 30-point gap.

Standout ZIPs in this County


Most Populous
Manchester · 8,193 people
50.4% of county total
Highest Income
Earlville · $89,697 median
1.2× county average
Largest Land Area
Manchester · 139.0 sq mi
Spans the most ground
Fastest Growth
Hopkinton · 40.1% (10-yr)
1,306 → 1,830 residents
Most Educated
Manchester · 26.8% bachelor's+
1,563 of 5,827 adults 25+

Things worth knowing about Delaware County


16,256 residents live across 10 ZIPs covering 542 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 15,802 to 16,121 from 2014 to 2024 — a +2.0% change. 5 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 52041 (Earlville, $89,697 median) and poorest ZIP 50654 (Masonville, $53,264) are 16.1 miles apart — a 1.7× income gap across local geography.

Median home values vary 2.1× across this county — from $124,100 in 50654 (Masonville) to $260,600 in 52330 (Ryan).

Density varies 55× across the county — from 5 people/sq mi in 50654 (Masonville) to 277 in 52036 (Delaware).

Educational attainment ranges from 8.7% bachelor's+ in 52050 (Greeley) to 38.9% in 52330 (Ryan) — the breadth of educational profiles across the area.

Within Iowa, this is the #43 most populous of 99 counties and ranks #45 for median household income .

Weighted by population, the typical household earns about $74,287 across the county — reflecting what a typical resident sees, not a simple ZIP average.

22.6% of adults age 25+ hold a bachelor's degree or higher (2,557 of 11,298 reporting).

10 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Delaware County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
542
square miles
Avg density
30.0
people per sq mi
Population
16,256
across 10 ZIPs
Manchester
139.0 sq mi
8,193 residents
Hopkinton
83.3 sq mi
1,830 residents
Earlville
57.8 sq mi
1,468 residents

All ZIP Codes in Delaware County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
52057ManchesterStandard8,193$69,635139.06.5%
52237HopkintonStandard1,830$84,06383.340.1%
52041EarlvilleStandard1,468$89,69757.8-3.9%
52035ColesburgStandard1,331$62,10947.317.1%
52223DelhiStandard1,199$89,25048.3-30.4%
52330RyanStandard940$86,53644.06.5%
52038DundeeStandard463$56,25027.58.4%
52050GreeleyStandard422$67,20640.2-45.0%
50654MasonvilleStandard275$53,26454.6-18.6%
52036DelawareStandard135$85,2080.5

Adjacent & Nearby Counties