Rules for ZIP Code 54421
Colby, WI · Marathon County
ZIP 54421 is governed by the city of Colby, WI. We do not hold its code yet, and Marathon County ordinances do not apply inside its limits.
ZIP code 54421 lies in the city of Colby, WI, which holds about 51% of the ZIP's residents and writes its own local code. We have not added Colby's ordinances yet, so nothing is shown below: Marathon County rules govern only unincorporated land and do not reach inside Colby.
ZIP codes do not follow city lines. 54421 also covers:
- town of Colby~21% of residents · not covered yet
- town of Hull~15% of residents · not covered yet
Shares are estimates from 2020 Census geography. If your address is in one of these, its rules apply instead.
Each topic below links to the full ordinance breakdown with specific code sections, fine amounts, and answers to common questions. The data is sourced from the official municipal code and verified by our editorial team.
Colby is not covered yet
The city of Colby writes its own code; the county's rules do not apply inside it.Request Colby coverage →
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