Fond du Lac County leans Republican by roughly 22 points: about 39% of voters vote Democratic and 61% Republican.
About 78% of adults in Fond du Lac County typically vote, above the U.S. average of about 62%. Among adults in Fond du Lac County, ~30% vote Democratic, ~48% Republican, and ~22% don't vote. The map below shows estimated turnout by block group.
How Fond du Lac County compares
Among counties within 50 miles, Fond du Lac County leans more Republican than 5 of 12 neighbors.
Fond du Lac County runs about 22 points more Republican than Wisconsin as a whole.
Politics vary noticeably by city within Fond du Lac County. The southeast side is the most Republican-leaning (R+48) and the north side is the least Republican-leaning (R+16), a spread of about 31 points.
Why Fond du Lac County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Fond du Lac County, not a ranked or complete list of what matters most.
Fond du Lac County votes Republican even though it is densely developed (about 50%, well above the Wisconsin average of 24%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Fond du Lac County, WI sits in the top quarter nationally on this measure.
Why turnout in Fond du Lac County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Fond du Lac County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 67%, about 7 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Winnebago County, WI R+3
- Dodge County, WI R+30
- Green Lake County, WI R+34
- Calumet County, WI R+23
- Washington County, WI R+28
- Sheboygan County, WI R+15
- Outagamie County, WI R+13
- Ozaukee County, WI R+7
- Waushara County, WI R+33
- Manitowoc County, WI R+24
Counties with Similar Populations
- Macon County, IL R+8
- Flathead County, MT R+32
- Bay County, MI R+18
- Adams County, PA R+35
- Cecil County, MD R+29
- Franklin County, MO R+48
- Wicomico County, MD D+6
- Limestone County, AL R+45
- Etowah County, AL R+49
- Daviess County, KY R+31
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.