Rock County is a true toss-up. About 51% of voters here vote Democratic and 49% Republican.
About 77% of adults in Rock County typically vote, above the U.S. average of about 62%. Among adults in Rock County, ~39% vote Democratic, ~38% Republican, and ~23% don't vote. The map below shows estimated turnout by block group.
How Rock County compares
Among counties within 50 miles, Rock County sits roughly in the middle of the political spectrum, with 8 neighbors leaning further in the place's direction and 2 leaning the other way.
Politically, Rock County sits close to the rest of Wisconsin.
Politics vary noticeably by city within Rock County. The south side runs the most Democratic (D+21) and the southeast side runs the most Republican (R+12), a spread of about 33 points.
Why Rock County leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Rock County. The lean here lands roughly where demographic data alone would predict.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; Rock County, WI sits in the top quarter nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in Rock County looks the way it does
Turnout in Rock County sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Winnebago County, IL D+7
- Walworth County, WI R+17
- Boone County, IL R+15
- Green County, WI R+11
- Jefferson County, WI R+21
- Dane County, WI D+48
- Stephenson County, IL R+14
- McHenry County, IL R+5
- Ogle County, IL R+28
- Waukesha County, WI R+14
Counties with Similar Populations
- Houston County, GA R+4
- Olmsted County, MN D+12
- Yellowstone County, MT R+25
- Maui County, HI D+19
- Hampshire County, MA D+45
- Ector County, TX R+42
- Portage County, OH R+12
- Johnson County, IN R+35
- Dorchester County, SC R+12
- Comal County, TX R+36
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Sources and methodology
Precinct-level voting records used to fit the model come from Wisconsin Elections Commission, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.