South Side is a Democratic stronghold. About 79% of voters here vote Democratic and 21% Republican.
About 61% of adults in South Side typically vote, near the U.S. average of about 62%. Among adults in South Side, ~48% vote Democratic, ~13% Republican, and ~39% don't vote. The map below shows estimated turnout by block group.
How South Side compares
Among neighborhoods within 5 miles, South Side leans more Democratic than 11 of 20 neighbors.
South Side runs about 34 points more Democratic than Massachusetts as a whole.
Politics vary noticeably by block within South Side. The northwest side is the most Democratic-leaning (D+65) and the northeast side is the least Democratic-leaning (D+43), a spread of about 22 points.
Why South Side leans the way it does
This analysis examined 14,881 data points per neighborhood to find what predicts political lean and turnout. The items below are a few correlations that stood out for South Side, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 61% of adults in South Side hold a bachelor's degree, about 33 points above the U.S. average of 28%. A high never-married share predicts Democratic voting, and about 51% of adults in South Side have never been married, above 83% of neighborhoods.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; South Side, Waltham, MA sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in South Side looks the way it does
Renters vote less often than owners. About 65% of households in South Side rent, about 40 points above the U.S. average of 25%. Learn more about the findings and methodology on the political spectrum map.
Nearby Neighborhoods
- Bleachery, Waltham, MA D+42
- Bank Square, Waltham, MA D+50
- Waltham Highlands, Waltham, MA D+43
- West Newton, Newton, MA D+60
- Nonantum, Newton, MA D+49
- Warrendale, Waltham, MA D+38
- Piety Corner, Waltham, MA D+37
- Lasell Village, Auburndale, MA D+57
- Bemis, Watertown Town, MA D+50
- The Lanes, Waltham, MA D+29
Neighborhoods with Similar Populations
- Pleasant Ridge, Cincinnati, OH D+55
- Alamedan Valley, North Valley, NM D+17
- Aberdeen, Hampton, VA D+72
- Sterling Park, Sterling, VA D+23
- East Falls, Philadelphia, PA D+75
- West Ward, Easton, PA D+27
- Arlington, Riverside, CA D+11
- Waialae-Kahala, Honolulu, HI D+27
- Silver Lakes, Pembroke Pines, FL D+16
- Rancho West, San Bernardino, CA D+18
Sources and methodology
Precinct-level voting records used to fit the model come from Massachusetts Secretary of the Commonwealth, 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.