The Commonwealth of Massachusetts has 14 Counties and 10 Congressional Districts: 5 counties are wholly within a congressional district; 9 counties are divided among more than one congressional district.

CD # 1 includes:

• the entirety of BERKSHIRE COUNTY;
• the entirety of FRANKLIN COUNTY;
• in HAMPDEN COUNTY: Blandford, Chester, Granville, Holyoke, Montgomery, Southwick, Tolland, Westfield and West Springfield;
• in HAMPSHIRE COUNTY: Amherst, Belchertown, Chesterfield, Cummington, Easthampton, Goshen, Granby, Hatfield, Huntington, Middlefield, Pelham, Plainfield, Southampton, Westhampton, Williamsburg and Worthington;
• in MIDDLESEX COUNTY: Ashby and Townsend;
• in WORCESTER COUNTY: Ashburnham, Athol, Barre, Fitchburg, Gardner, Hardwick, Hubbardston, Leominster, New Braintree, North Brookfield, Oakham, Petersham, Phillipston, Royalston, Templeton, West Brookfield, Westminster and Winchendon.

the Town of Lunenburg (Worcester County) is mostly in CD 1 but a small portion lies in CD 5.

CD # 2 includes:

• in HAMPDEN COUNTY: Agawam, Brimfield, Chicopee, East Longmeadow, Hampden, Holland, Longmeadow, Ludlow, Monson, Palmer, Springfield, Wales and Wilbraham;
• in HAMPSHIRE COUNTY: Hadley, Northampton, South Hadley and Ware;
• in NORFOLK COUNTY: Bellingham;
• in WORCESTER COUNTY: Blackstone, Brookfield, Charlton, Douglas, Dudley, East Brookfield, Leicester, Mendon, Milford, Millbury, Millville, Oxford, Southbridge, Sturbridge, Sutton, Uxbridge, Warren and Webster.

the Town of Auburn (Worcester County) is mostly in CD 2 but a small portion lies in CD 3.

CD # 3 includes:

• in BRISTOL COUNTY: Attleboro, Dartmouth, North Attleborough, Seekonk, Somerset, Swansea and Westport;
• in MIDDLESEX COUNTY: Holliston and Hopkinton;
• in NORFOLK COUNTY: Franklin, Medway, Plainville and Wrentham;
• in WORCESTER COUNTY: Berlin, Boylston, Clinton, Grafton, Holden, Northborough, Northbridge, Paxton, Princeton, Rutland, Shrewsbury, Sterling, Upton, Westborough, West Boylston and Worcester.

the City of Fall River (Bristol County) is split between CDs 3 and 4.
the Town of Foxborough (Norfolk County) is split between CDs 3 and 4.
the Town of Lancaster (Worcester County) is split between CDs 3 and 5.
the Town of Mansfield (Bristol County) is mostly in CD 3 but a small portion lies in CD 4.

CD # 4 includes:

• in BRISTOL COUNTY: Acushnet, Berkley, Dighton, Fairhaven, Freetown, New Bedford, Norton, Raynham and Rehoboth;
• in MIDDLESEX COUNTY: Sherborn;
• in NORFOLK COUNTY: Brookline, Dover, Millis, Norfolk, Sharon and Wellesley;
• in PLYMOUTH COUNTY: Bridgewater, Carver, East Bridgewater, Halifax, Hanson, Lakeville, Marion, Mattapoisett, Middleborough, Pembroke, Plympton, Rochester, Wareham and West Bridgewater.

the Town of Rockland (Plymouth County) is split between CDs 4 and 10.

CD # 5 includes:

• in ESSEX COUNTY: Andover, Lawrence and Methuen;
• in MIDDLESEX COUNTY: Acton, Ashland, Ayer, Billerica, Boxborough, Carlisle, Chelmsford, Concord, Dracut, Dunstable, Groton, Hudson, Littleton, Lowell, Marlborough, Maynard, Pepperell, Shirley, Stow, Sudbury, Tewksbury, Tyngsborough, Wayland and Westford;
• in WORCESTER COUNTY: Bolton, Harvard and Southborough.

as noted earlier, the Town of Lancaster (Worcester County) is split between CDs 3 and 5.

CD # 6 includes:

• in ESSEX COUNTY: Amesbury, Beverly, Boxford, Danvers, Essex, Georgetown, Gloucester, Groveland, Hamilton, Haverhill, Ipswich, Lynn, Lynnfield, Manchester, Marblehead, Merrimac, Middleton, Nahant, Newbury, Newburyport, North Andover, Peabody, Rockport, Rowley, Salem, Salisbury, Saugus, Swampscott, Topsfield, Wenham and West Newbury;
• in MIDDLESEX COUNTY: Bedford, Burlington, North Reading and Wilmington.

the Town of Reading (Middlesex County) is split between CDs 6 and 7.

CD # 7 includes:

• in MIDDLESEX COUNTY: Arlington, Everett, Framingham, Lexington, Lincoln, Malden, Medford, Melrose, Natick, Stoneham, Wakefield, Waltham, Weston, Winchester and Woburn;
• in SUFFOLK COUNTY: Revere and Winthrop.

CD # 8 includes:

• in MIDDLESEX COUNTY: Belmont, Cambridge, Somerville and Watertown;
• in SUFFOLK COUNTY: a portion of the City of Boston plus Chelsea.

CD # 9 includes:

• in BRISTOL COUNTY: Taunton.
• in NORFOLK COUNTY: Braintree, Canton, Dedham, Medfield, Milton, Needham, Norwood, Randolph, Stoughton, Walpole and Westwood;
• in SUFFOLK COUNTY: a portion of the City of Boston.

the City of Brockton (Plymouth County) is split between CDs 9 and 10.
the Town of Easton (Bristol County) is mostly in CD 9 but a small portion lies in CD 4.

CD # 10 includes:

• the entirety of BARNSTABLE COUNTY (=Cape Cod);
• the entirety of DUKES COUNTY (=Martha's Vineyard plus the Elizabeth Islands);
• the entirety of NANTUCKET COUNTY (=the island of Nantucket)
• in NORFOLK COUNTY: Avon, Cohasset, Holbrook, Quincy and Weymouth;
• in PLYMOUTH COUNTY: Abington, Duxbury, Hanover, Hingham, Hull, Kingston, Marshfield, Norwell, Plymouth, Scituate and Whitman.

as noted earlier, the Town of Rockland (Plymouth County) is split between CDs 4 and 10.