mapoli

Massachusetts Legislative District Atlas with interactive maps, demographics, and election history for all 217 State Representative, State Senate, Governor’s Council, and U.S. House districts.

Massachusetts Legislative District Atlas

Interactive maps and demographic data for all 217 Massachusetts legislative districts

September Primaries

The Massachusetts state primary is September 1, 2026. Below is a count of the legislative districts with a contested primary — where more than one candidate of the same party is on the ballot.

Office Districts
Contested Primaries
Democratic Republican
State Representative 34 31 4
State Senate 7 6 1
Governor's Council 4 4 0
U.S. House 6 6 0

See the September 2026 primary candidates page for the Democratic and Republican candidates in each of those districts, grouped by office, with incumbents and open seats marked.

Fun Facts

The largest and smallest State Rep districts

  • While every mapoli State Representative district has approximately the same population (currently about 44,000 people) the districts vary widely in geographic size.
  • The smallest State Representative district in terms of area is Ways and Means Chair Aaron Michlewitz’s Third Suffolk district coming in at a petite 1.36 square miles.
  • The largest State Representative district is the Third Berkshire district represented by Leigh Davis of Great Barrington. The district covers a whopping 551 square miles and contains 18 separate municipalities.

Statewide District Overviews and Comparisons

The district atlas contains statewide maps for each legislative office with district-to-district comparison tables on political and demographic data.

Example office page

Per-District Map, Demographics, and Election Information

There is also a separate page for each of the 160 State Representative, 40 State Senate, 9 U.S. House, and 8 Governor’s Council districts with demographic details and electon results back to 1990.

Example district page

Full Legislative District List

The full list of 160 State Representative, 40 State Senate, 8 Governor’s Council, 9 U.S. House districts.

Massachusetts Legislative Districts