San Ysidro leans heavily Democratic by roughly 36 points: about 68% of voters vote Democratic and 32% Republican.
About 56% of adults in San Ysidro typically vote, below the U.S. average of about 62%. Among adults in San Ysidro, ~38% vote Democratic, ~18% Republican, and ~44% don't vote. The map below shows estimated turnout by block group.
How San Ysidro compares
Among cities within 25 miles, San Ysidro leans more Democratic than 8 of 19 neighbors.
San Ysidro runs about 29 points more Democratic than New Mexico as a whole.
Politics vary noticeably by neighborhood within San Ysidro. The northeast side runs the most Democratic (D+62) and the northwest side runs the most Republican (R+4), a spread of about 66 points.
Why San Ysidro 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 Ysidro, not a ranked or complete list of what matters most.
Areas with many never-married adults vote Democratic. About 62% of adults in San Ysidro have never been married, far above similar-sized cities (around 25%).
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; San Ysidro, NM 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 San Ysidro looks the way it does
Crowded housing lines up with lower turnout. About 8% of homes in San Ysidro have more than one occupant per room, above 95% of cities. High-crime urban areas turn out at lower rates, and San Ysidro sits in the top 15% on a violent-crime measure. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Zia Pueblo, NM D+36
- Jemez Pueblo, NM D+51
- Ponderosa, NM D+19
- Ranchitos, NM R+14
- Jemez Springs, NM R+3
- Rio Rancho, NM R+4
- Bernalillo, NM D+10
- Algodones, NM D+51
- San Felipe Pueblo, NM D+57
Cities with Similar Populations
- Marshallberg, NC R+48
- Zion, PA R+38
- Fort Laramie, WY R+80
- Davidson, OK R+70
- Chandler Springs, AL R+66
- Slabtown, OH R+65
- Walthall, MS R+73
- Free Trade, MS R+40
- Norton, WV R+65
- Filley, NE R+64
Sources and methodology
Precinct-level voting records used to fit the model come from New Mexico Secretary of State, Bureau 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.