Thornhill, VA Political Map | Democrat & Republican Areas in Thornhill

Thornhill leans heavily Republican by roughly 46 points: about 27% of voters vote Democratic and 73% Republican.

 
Thornhill, VA block-group political-lean map
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About 82% of adults in Thornhill typically vote, above the U.S. average of about 62%. Among adults in Thornhill, ~22% vote Democratic, ~60% Republican, and ~18% don't vote. The map below shows estimated turnout by block group.

Thornhill, VA block-group voter-turnout map
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How Thornhill compares

Among cities within 25 miles, Thornhill leans more Republican than 76 of 84 neighbors.

Thornhill runs about 52 points more Republican than Virginia as a whole. Virginia leans Democratic overall, while Thornhill is one of the few Republican-leaning pockets.

Why Thornhill 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 Thornhill, not a ranked or complete list of what matters most.

Thornhill votes against the grain of Virginia. Virginia leans Democratic overall, while Thornhill runs about 52 points more Republican. A high family-household share predicts Republican voting, and about 79% of households in Thornhill are family households, above 86% of cities.

Homeownership and voter turnout

Places with homeowner-heavy households tend to turn out at a higher rate; Thornhill, VA sits in the top quarter nationally on this measure.

Why turnout in Thornhill looks the way it does

Homeowners vote more often than renters. About 90% of households in Thornhill own their home, about 14 points above the Virginia average of 76%. Learn more about the findings and methodology on the political spectrum map.

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Sources and methodology

Precinct-level voting records used to fit the model come from Virginia Department of 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.