Where the map comes from
District lines
U.S. Census Bureau 2024 cartographic boundary files (1:500,000): cb_2024_us_cd119_500k (Massachusetts features only) for the 9 U.S. House districts, cb_2024_25_sldu_500k for the 40 state Senate districts, cb_2024_25_sldl_500k for the 160 state House districts, cb_2024_us_county_500k for counties and cb_2024_25_place_500k for city and town limits. These show the Massachusetts Legislature's 2021 state Senate and House districts. District files are converted without simplification; county outlines and city limits are simplified for display. Near a boundary line they can be off by a block or more.
Files
cb_2024_25_sldu_500k.zip: www2.census.gov, retrieved 2026-10-13cb_2024_25_sldl_500k.zip: www2.census.gov, retrieved 2026-10-13cb_2024_25_place_500k.zip: www2.census.gov, retrieved 2026-10-13ma.csv: data.openstates.org, retrieved 2026-10-13FAILED (http 302, got: cannot open `IFV_2026 English.pdf.part' , bytes): sec.state.ma.us, retrieved 2026-10-13
Census files: www2.census.gov/geo/tiger/GENZ2024/shp/.
Software
Leaflet 1.9.4 (BSD-2-Clause), served from this site. Optional street map © OpenStreetMap contributors; optional address search by OpenStreetMap Nominatim.