Massachusetts's 3rd congressional district

Massachusetts's 3rd congressional district is located in north-central and northeastern Massachusetts. The largest municipalities in the district are Lowell, Lawrence, Haverhill, Methuen, Billerica (partial), Fitchburg, and Marlborough.

Democrat Lori Trahan has represented the district since 2019.

Cities and towns in the district
As of the 2021 redistricting, the 3rd district contains 35 municipalities:


 * Essex County: Haverhill, Lawrence, Methuen
 * Middlesex County: Acton, Ashby, Ayer, Billerica (only precincts 1, 2, 6, 7, 8, 11, & 12),Boxborough, Carlisle, Chelmsford, Concord, Dracut, Dunstable, Groton, Hudson, Littleton, Lowell, Marlborough, Pepperell, Shirley, Stow, Townsend, Tyngsborough, Westford
 * Worcester County: Ashburnham, Berlin, Bolton, Clinton, Fitchburg, Gardner, Harvard, Lancaster, Lunenburg, Westminster (only precincts 1, 2, & 3), Winchendon

History of District Boundaries
After the 2010 census, the third district shifted from covering east-central Worcester County and western Norfolk and Bristol Counties to covering northeastern Worcester County, northern and western Middlesex County, and northwestern Essex county. The old 3rd district area was largely split between the updated 2nd and 4th districts. Only Clinton and Marlborough carried over from the old 3rd district.

In the redistricting that occurred after the 2020 census, the boundaries of the third district only changed slightly from its previous iteration.

Historical district boundaries
From 2003-2013: In Bristol County: Attleboro, Fall River (Wards 1–3; Ward 4, Precincts A and B; Ward 5, Precincts A and B; Ward 6, Precincts B and C; and Ward 8, Precinct D), North Attleborough, Rehoboth, Seekonk, Somerset, Swansea.

In Middlesex County: Ashland, Holliston, Hopkinton, Marlborough.

In Norfolk County: Franklin, Medway, Plainville, Wrentham.

In Worcester County: Auburn, Boylston, Clinton, Holden, Northborough, Paxton, Princeton, Rutland, Shrewsbury, Southborough, West Boylston, Westborough, Worcester.