Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — CITY/IA/ONSLOW

Onslow ZIP code, Iowa

The ZIP code for Onslow, IA is 52321, and its area code is 563.

USPS city name
1 ZIP code
Population
284
Area code
563
State
Iowa

Onslow in numbers

About 284 people live in Onslow, in 96 households. The median household income is $65,313 a year, 13% below the Iowa median of $75,059 (US: $80,734). The median owner-occupied home is valued at $100,000 (52% below the Iowa median), and median gross rent is $1,250 a month. The median age is 30.0; 14.8% of adults 25 and over hold a bachelor's degree or higher (31.4% across Iowa); the average commute takes 30 minutes.

Population284Onslow284
Households96Onslow96
Median age30.0Onslow30.0Iowa38.6US 38.9
Median household income$65,313Onslow$65,313Iowa$75,059US $80,734
Median home value$100,000Onslow$100,000Iowa$208,000US $332,700
Median gross rent$1,250Onslow$1,250Iowa$972US $1,413
Bachelor's degree or higher14.8%Onslow14.8%Iowa31.4%US 35.7%
Mean commute30.3 minOnslow30.3 minIowa19.8 minUS 26.4 min
Population density1,464 / sq miOnslow1,464 / sq mi

U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, for the census place Onslow city. Survey estimates carry margins of error, wider for small places. Sources and methods.

ZIP codes addressed as Onslow

ZIP codes with the USPS city name Onslow
ZIP City Type Population Median income Median home
52321 Onslow , IA Standard 395 $77,708 $131,300

Map of Onslow ZIP codes

52321

The ZIP codes of Onslow, IA, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.

Towns near Onslow

The nearest larger towns are Wyoming (525 people, 3.3 mi), Oxford Junction (461 people, 9.1 mi) and Olin (830 people, 10.0 mi).

Towns near Onslow
TownPopulationDistance
Monticello 4,071 12.2 mi
Anamosa 5,629 13.3 mi
Maquoketa 6,075 18.3 mi
Tipton 3,106 24.0 mi
Mount Vernon 4,513 24.6 mi
Dyersville 4,423 26.4 mi
Marion 41,896 29.6 mi

More nearby: every ZIP code in Jones County · Iowa ZIP codes

Cite this page

zipcodes.pro. “Onslow, IA ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/city/ia/onslow

Underlying data is public domain or openly licensed — sources, vintages and licences.