Rancho Cucamonga, CA Political Map | Democrat & Republican Areas in Rancho Cucamonga

By the BestNeighborhood data science team. Last updated May 2026.

Rancho Cucamonga is a true toss-up. About 51% of voters here vote Democratic and 49% Republican.

 

About 60% of adults in Rancho Cucamonga typically vote, near the U.S. average of about 62%. Among adults in Rancho Cucamonga, ~31% vote Democratic, ~29% Republican, and ~40% don't vote. The map below shows estimated turnout by block group.

How Rancho Cucamonga compares

Among cities within 25 miles, Rancho Cucamonga sits roughly in the middle of the political spectrum, with 38 neighbors leaning further in the place's direction and 39 leaning the other way.

Rancho Cucamonga runs about 19 points more Republican than California as a whole.

Politics vary noticeably by neighborhood within Rancho Cucamonga. The south side runs the most Democratic (D+12) and the northwest side runs the most Republican (R+15), a spread of about 27 points.

Why Rancho Cucamonga leans the way it does

Density, race composition, education, and family structure all sit close to their national averages in Rancho Cucamonga. The lean here lands roughly where demographic data alone would predict.

Population density and Democratic lean

Places with high population density tend to lean Democratic; Rancho Cucamonga, CA sits in the top tenth nationally on this measure.

Why turnout in Rancho Cucamonga looks the way it does

Renters vote less often than owners. About 37% of households in Rancho Cucamonga rent, about 12 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 5% of homes in Rancho Cucamonga have more than one occupant per room, above 89% of cities. Learn more about the findings and methodology on the political spectrum map.

Sources and methodology

Precinct-level voting records used to fit the model come from California Secretary of State, Elections, 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.