Boulder Oaks, CA Political Map | Democrat & Republican Areas in Boulder Oaks

Boulder Oaks leans Republican by roughly 30 points: about 35% of voters vote Democratic and 65% Republican.

 
Boulder Oaks, CA block-group political-lean map
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About 45% of adults in Boulder Oaks typically vote, below the U.S. average of about 62%. Among adults in Boulder Oaks, ~16% vote Democratic, ~29% Republican, and ~55% don't vote. The map below shows estimated turnout by block group.

Boulder Oaks, CA block-group voter-turnout map
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How Boulder Oaks compares

Among cities within 25 miles, Boulder Oaks leans more Republican than 9 of 23 neighbors.

Boulder Oaks runs about 49 points more Republican than California as a whole. California leans Democratic overall, while Boulder Oaks is one of the few Republican-leaning pockets.

Politics vary noticeably by neighborhood within Boulder Oaks. The south side is the most Republican-leaning (R+34) and the southwest side is the least Republican-leaning (R+14), a spread of about 20 points.

Why Boulder Oaks leans the way it does

This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Boulder Oaks, not a ranked or complete list of what matters most.

Boulder Oaks votes against the grain of California. California leans Democratic overall, while Boulder Oaks runs about 49 points more Republican. Rural areas vote Republican, and Boulder Oaks sits in the bottom quarter on density (about 3%, below 92% of cities). A high family-household share predicts Republican voting, and about 75% of households in Boulder Oaks are family households, above 77% of cities.

Paved land cover and Republican lean

Places with little paved surface tend to lean Republican; Boulder Oaks, CA sits in the bottom tenth 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 Boulder Oaks looks the way it does

Areas with limited routine healthcare access turn out at lower rates. Boulder Oaks is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. High food insecurity lines up with lower turnout, and about 22% of adults in Boulder Oaks report food insecurity, above 86% of cities. Learn more about the findings and methodology on the political spectrum map.

Cities with Similar Populations

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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.