What city is ZIP code 54421?

ZIP code 54421 is in Colby, WI (Marathon County).

What county is ZIP code 54421 in?

ZIP code 54421 is mostly in Marathon County, Wisconsin.

How many people live in ZIP code 54421?

About 3,468 people live in the 54421 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Checked Oct 26, 2026

ZIP Code 54421

Colby, WI, Marathon County

Population

3,468

Land area

69.9sq mi

People per sq mi

City

Colby

ZIP 54421 and nearby ZIP codes

Full map

ZIP 54421 at a glance

ZIP 54421 (Colby) is 55% less dense than Wisconsin as a whole.
The median household income is $60,820, 22% below the Wisconsin median of $77,485.
A typical owner-occupied home is valued at $194,500 (27% below Wisconsin) and median rent is $844 a month.

Local data for ZIP 54421

Counts from official public data

Housing and community stats

ZIP 54421, American Community Survey 2020-2024

Full profile

Median household income

$60,820

Poverty rate

13.7%

Median home value

$194,500

Prices +3.9% in a year

Median rent

$844/mo

Homeownership

68.3%

Bachelor's or higher

13.9%

Median age

36.8

Average commute

18.7 min

Income, education and commute

Economy and federal money

Businesses, pandemic loans and political donations

Details

Business establishments

ZIP Business Patterns 2023

Employees

951

$47.5M annual payroll

PPP loans

$5M

99 loans

Campaign donations

$1,416

20% D, 37% R, 2026 cycle

PPP loans in this ZIP

Environment and hazard risk

ZIP 54421, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Relatively Moderate

Top: cold wave

Storm events since 1996

753

Countywide, mostly hail

Flood insurance policies

199

0.4% of homes, county

July high / Jan low

79° / 2°F

34.2 inches of rain a year

Hazards, floods and storm history Check a flood zone

Health statistics

Share of adults in ZIP 54421, CDC PLACES estimates

All 40 measures

Obesity

38.7%

U.S. 33.3% +5.4 pts

Diabetes

13.0%

U.S. 12.1% +0.9 pts

Smoking

18.6%

U.S. 12.8% +5.8 pts

Uninsured (18-64)

12.8%

U.S. 11.1% +1.7 pts

Frequently asked questions

What city is ZIP code 54421?: ZIP code 54421 is in Colby, WI (Marathon County).
What county is ZIP code 54421 in?: ZIP code 54421 is mostly in Marathon County, Wisconsin.
How many people live in ZIP code 54421?: About 3,468 people live in the 54421 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Source: U.S. Census Bureau (ZIP Code Tabulation Areas, American Community Survey) · Data as of 12/31/2023. ZIP Code Tabulation Areas closely match, but are not identical to, USPS ZIP code delivery areas.