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MassGIS Data: Massachusetts Senate Legislative Districts (2012)

March 2022

*** For the latest data see the 2021 State Senate districts.

This layer shows the most current State Senate district boundaries for Massachusetts that were used in elections beginning in 2012 and those before 2022. Voting resources can be found on the Secretary of the Commonwealth’s website.

Table of Contents



The Massachusetts Senate Legislative Districts datalayer reflects the state Senate district boundaries as defined by Massachusetts General Laws, Chapter 57: Section 3. These 40 districts are those used in the Fall 2012 elections and beyond, until they are redrawn using the 2020 decennial Census.

The names of the statewide datalayers are SENATE2012_POLY (polygons) and SENATE2012_ARC (arcs). These replace the previous SENATE02_ARC and SENATE02_POLY layers.


Staff at the Massachusetts Senate developed this layer with its contractor, Caliper Corp. (Newton, MA), using Maptitude for Redistricting software. MassGIS appended the 1:100,000 coastline and state outline and added the senators' name and party attributes.

In March 2018 MassGIS made minor edits to boundaries in Boston to reflect corrected data from the City of Boston. In November 2018 MassGIS made minor edits to boundaries statewide where they were offset enough from survey-based municipal lines to result in address points being assigned to the wrong district. These boundary changes have not been incorporated into U.S. Census geography that forms the basis for this layer. In January 2021, the layer was updated to reflect the results of the latest elections.


The SENATE2012_POLY attribute table has the following fields:

SENDISTNUM 5 / I Senate District number
SEN_DIST 43 / C Name of Senate District
SEN_FIRST 13 / C First name of Senator
SEN_LAST 15 / C Last name of Senator
SEN_PARTY 3 / C Senator's political party
SENATOR 40 / C Senator's full name and party
URL 150 / C Senator's Web site address

In the SENATE2012_ARC attribute table, the field OUTLINE is coded as follows:

  • 0 = Internal district boundaries
  • 1 = State
  • 2 = Coastline


*** These data layers have been superseded by the 2021 state Senate districts.

MassGIS maintains the layer. Last updated March 10, 2022.

Also see the state House and Congress data layers.

Visit the Commonwealth's Find Your Legislators page

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