Massachusetts is divided into five distinct numbering plan areas (NPAs) in the North American Numbering Plan (NANP), which are served by nine area codes, organized as four overlay complexes and a single-area code NPA.
Eastern Massachusetts has area codes 339, 351, 508, 617, 774, 781, 857, and 978. Western Massachusetts has area code 413.
The numbering plan areas are organized into two local access and transport areas (LATAs): 126 comprises the western part, and 128 covers the central and eastern parts.