ZIP Codes of Cass County, IA

Population & People
Population & People
Total Population
13,872
Household Income
Household Income
Median Income
$68,278
Housing
Housing
Total Housing Units
6,717
Business & Economy
Business & Economy
Total Businesses
451
Employment
Employment
Employment Rate
62.91%
Education
Education
Bachelor's Degree+
22.35%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 8 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:8 ZIP Codes (8 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:712
Timezone:Central (GMT -06:00)
Local Time:2:11:51 PM
Population:13,872 [See All]
FIPS:19029
Land Area:671 sq mi
Water Area:1 sq mi
Coordinates:41.3439, -94.9657
Quick Link:
https://www.zip-codes.com/county/ia-cass.asp
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Among America's 50 most Hispanic-majority counties
0.4% Hispanic or Latino — #30 nationwide.

Standout ZIPs in this County


Most Populous
Atlantic · 8,526 people
61.5% of county total
Highest Income
Marne · $90,000 median
1.3× county average
Largest Land Area
Atlantic · 167.3 sq mi
Spans the most ground
Fastest Growth
Atlantic · 5.0% (10-yr)
8,117 → 8,526 residents
Most Educated
Atlantic · 24.9% bachelor's+
1,482 of 5,962 adults 25+

Things worth knowing about Cass County


13,872 residents live across 8 ZIPs covering 671 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 14,220 to 13,872 from 2014 to 2024 — a -2.4% change. 1 ZIPs gained residents, 7 lost.

The county's wealthiest ZIP 51552 (Marne, $90,000 median) and poorest ZIP 51544 (Lewis, $48,313) are 11.9 miles apart — a 1.9× income gap across local geography.

Median home values vary 2.1× across this county — from $81,000 in 51544 (Lewis) to $169,100 in 50853 (Massena).

Density varies 11× across the county — from 5 people/sq mi in 51552 (Marne) to 51 in 50022 (Atlantic).

Educational attainment ranges from 11.0% bachelor's+ in 51552 (Marne) to 24.9% in 50022 (Atlantic) — the breadth of educational profiles across the area.

Within Iowa, this is the #57 most populous of 99 counties and ranks #79 for median household income .

Weighted by population, the typical household earns about $65,266 across the county — reflecting what a typical resident sees, not a simple ZIP average.

22.3% of adults age 25+ hold a bachelor's degree or higher (2,175 of 9,733 reporting).

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

Stories about Cass 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
671
square miles
Avg density
20.7
people per sq mi
Population
13,872
across 8 ZIPs
Atlantic
167.3 sq mi
8,526 residents
Griswold
131.2 sq mi
1,697 residents
Anita
96.5 sq mi
1,197 residents

Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Atlantic

All ZIP Codes in Cass County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
50022AtlanticStandard8,526$63,125167.35.0%
51535GriswoldStandard1,697$76,371131.2-10.7%
50020AnitaStandard1,197$75,41796.5-11.1%
51544LewisStandard793$48,31351.2-8.9%
50853MassenaStandard716$65,20873.7-1.8%
50843CumberlandStandard540$56,12568.6-17.1%
50274WiotaStandard234$71,66746.5-27.8%
51552MarneStandard169$90,00036.4-39.9%

Adjacent & Nearby Counties