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MassGIS Data: U.S. Congressional Districts (117th)

January 2021

The U.S. Congressional Districts datalayer reflects the current U.S. House of Representatives voting district boundaries for Massachusetts.

Table of Contents



These boundaries took effect in January 2012. The name of the statewide datalayers are CONGRESSMA_POLY and CONGRESSMA_ARC.


Staff at the Massachusetts General Court Special Joint Committee on Redistricting 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 Representatives' 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 CONGRESSMA_POLY attribute table has the following fields:

DIST_NUM 2 / I Unique number for each district
DISTRICT 50 / C District name
REP_FIRST 16 / C First name of representative
REP_LAST 16 / C Last name of representative
REP_PARTY 1 / C Political party of representative ((D) = Democrat)
REP 25 / C Rep.'s full name and party
URL 50 / C Web address for Representative
DISTRICT 3 / I Meeting number of the current Congress (116)

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

  • 0 = internal district boundaries
  • 1 = state
  • 2 = coastline


MassGIS maintains the layer and will make updates as needed. In January 2015 the polygon attributes were updated with the information for members of the 114th Congress. Additionally, the layers were renamed, the CD113 field was renamed DIST_NUM, and the DISTRICT field was added to the polygon feature class. In January 2021, the layer was updated with the results of the November 2020 elections.

Also see the state House and Senate data layers.