San Mateo is a Republican stronghold. About 20% of voters here vote Democratic and 80% Republican.
About 91% of adults in San Mateo typically vote, above the U.S. average of about 62%. Among adults in San Mateo, ~18% vote Democratic, ~72% Republican, and ~10% don't vote. The map below shows estimated turnout by block group.
How San Mateo compares
Among cities within 25 miles, San Mateo leans more Republican than 27 of 43 neighbors.
San Mateo runs about 46 points more Republican than Florida as a whole.
Politics vary noticeably by neighborhood within San Mateo. The south side is the most Republican-leaning (R+64) and the northeast side is the least Republican-leaning (R+47), a spread of about 17 points.
Why San Mateo 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 San Mateo, not a ranked or complete list of what matters most.
San Mateo votes Republican even though it is densely developed (about 20%, far below the Florida average of 57%). Here an older population outweighs the Democratic lean that density usually predicts.
Housing overcrowding and voter turnout
Places with low overcrowding tend to turn out at a higher rate; San Mateo, FL sits in the bottom tenth nationally on this measure.
Why turnout in San Mateo looks the way it does
Areas with limited routine healthcare access turn out at lower rates. San Mateo is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 48%, about 8 points below the Florida average of 56%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Yelvington, FL R+48
- Lundy, FL R+63
- Satsuma, FL R+58
- East Palatka, FL R+48
- Palatka, FL R+18
- Pomona Park, FL R+58
- Flagler Estates, FL R+58
- Welaka, FL R+55
Cities with Similar Populations
- Hamburg, OH R+48
- Jerome, IL D+16
- Garrison, ND R+58
- Mount Pulaski, IL R+48
- Hooker, OK R+59
- Cleveland, NY R+29
- Kirbyville, MO R+65
- Hustisford, WI R+42
- Questa, NM D+24
- Fleming, GA R+7
Sources and methodology
Precinct-level voting records used to fit the model come from Florida Division 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.