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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/WI/COLBY

Colby ZIP code, Wisconsin

The ZIP code for Colby, WI is 54421, and its area codes are 715 and 534.

USPS city name
1 ZIP code
Population
1,907
Area codes
715, 534

Colby in numbers

About 1,907 people live in Colby, in 689 households. The median household income is $50,114 a year, 35% below the Wisconsin median of $77,485 (US: $80,734). The median owner-occupied home is valued at $184,700 (31% below the Wisconsin median), and median gross rent is $854 a month. The median age is 38.3; 16.1% of adults 25 and over hold a bachelor's degree or higher (33.4% across Wisconsin); the average commute takes 20 minutes.

Population1,907Colby1,907
Households689Colby689
Median age38.3Colby38.3Wisconsin40.2US 38.9
Median household income$50,114Colby$50,114Wisconsin$77,485US $80,734
Median home value$184,700Colby$184,700Wisconsin$266,500US $332,700
Median gross rent$854Colby$854Wisconsin$1,087US $1,413
Bachelor's degree or higher16.1%Colby16.1%Wisconsin33.4%US 35.7%
Mean commute20.4 minColby20.4 minWisconsin22.2 minUS 26.4 min
Population density1,164 / sq miColby1,164 / sq mi

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

ZIP codes addressed as Colby

ZIP codes with the USPS city name Colby
ZIP City Type Population Median income Median home
54421 Colby , WI Standard 3,468 $60,820 $194,500

Map of Colby ZIP codes

54421

The ZIP codes of Colby, WI, 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 Colby

The nearest larger towns are Abbotsford (2,024 people, 2.2 mi), Medford (4,431 people, 16 mi) and Marshfield (18,700 people, 19 mi).

Towns near Colby
TownPopulationDistance
Medford 4,431 15.5 mi
Marshfield 18,700 18.5 mi

More nearby: every ZIP code in Marathon County · Wisconsin ZIP codes

Cite this page

zipcodes.pro. “Colby, WI ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/city/wi/colby

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