Mass Bay Credit Union is expanding its field of membership to include all of Suffolk and Norfolk Counties, adding several towns to its territory.

The expansion allows residents of Abington, Everett, Hanover, Hingham, Lynn, Malden, Marshfield, Medford, Melrose, Norwell, Peabody, Rockland, Saugus, Scituate, Somerville, Stoneham and Whitman to become members of the South Boston-based credit union.

Mass Bay said extending its field of membership gives it access to nearly 2 million residents.