Rock County, Wisconsin
Rock County is a county in Wisconsin. Its county FIPS code is 55105. Use the boundary map and neighboring areas below to check the jurisdiction you need.
- Official code
- 55105
- Representative coordinates
- 42.669880, -89.075284
- County type
- County
- County seat or government
- Janesville
- Resident population, July 2025
- 166,472
- Land area
- 1,860.046 km²
- Water area
- 20.694 km²
- State
- Wisconsin
The representative point identifies this area. It is not a street address or a boundary survey.
Time zones in Rock County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| America/Chicago | UTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Listed zones overlap the mapped area. A point lookup can distinguish sides of a boundary. Your device’s zone may differ.
Census ZIP areas
53114 · 53190 · 53501 · 53502 · 53505 · 53511 · 53520 · 53521 · 53525 · 53534 · 53536 · 53537 · 53538 · 53545 · 53546 · 53548 · 53563 · 53576 · 53585 · 53589
These statistical areas overlap the boundary. They are not delivery assignments; confirm mailing details with USPS ZIP Code Lookup.
Official county information
Rock County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Cities, towns and communities
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
Areas sharing the mapped boundary
These areas touch this mapped boundary.
Before using this answer on a form
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