Where is Rock County?

3 Rock Counties in 3 states · 177,255 people (2025)

There are 3 counties named Rock County in the United States, in Minnesota, Nebraska and Wisconsin. The most populous is Rock County, Wisconsin (county seat: Janesville), with 166,472 people in 2025.

Map of the United States showing where all 3 Rock Counties are, labeled by state
Every Rock County in the United States (red), labeled with its state. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).

All 3 Rock Counties

Sorted by state. Each link opens the county's map.

StateCounty seatPopulation 2025Land area (sq mi)EstablishedNamed after
Rock County, MinnesotaLuverne9,5244831857–
Rock County, NebraskaBassett1,2591,0081888–
Rock County, WisconsinJanesville166,4727181836–

Questions about Rock Counties

How many Rock Counties are there?

There are 3 Rock Counties in the United States, in Minnesota, Nebraska and Wisconsin.

Which Rock County is the largest?

By population, Rock County, Wisconsin (166,472 people in 2025). By land area, Rock County, Nebraska (1,008 sq mi).

Which Rock County is the oldest?

Rock County, Wisconsin, established in 1836. The newest is Rock County, Nebraska (1888).

How do I find out which Rock County an address is in?

Open the county map of the state: it has a search box for cities, towns and ZIP codes. On a phone, the "what county am I in" tool on our sister site uses your location.

What county am I in? →

Other common county names