Boston is served by 8 active area codes as of 2026, layered through decades of overlays and splits across the metro area. This guide walks through which code covers which part of the region, why so many codes are needed, and what new codes may come next.
The Short Answer
Boston currently has 8 active area codes in service. The count reflects a combination of population growth, the rise of mobile lines, and the way modern numbering allocates blocks — every line activated, whether a cellphone, a business desk line, a VoIP number, or a connected device, consumes a slot in the pool.
Boston has roughly 5,025,517 residents as of the most recent estimates. That population, combined with the spread of mobile and VoIP lines per household, determines how often new area codes are needed.
The Full List of Boston Area Codes
The active area codes serving Boston are listed below, in numerical order. Where a code is an overlay or a split-off from an earlier code, that relationship is noted.
- 617 — City of Boston and inner communities (Brookline, Cambridge, Newton, Quincy)
- 857 — City of Boston and inner communities (overlay of 617)
- 781 — Inner suburbs along the Route 128 corridor and the South Shore
- 339 — Inner suburbs along the Route 128 corridor and the South Shore (overlay of 781)
- 508 — South-central and southeastern Massachusetts (Worcester, Framingham, Brockton, Fall River)
- 774 — South-central and southeastern Massachusetts (overlay of 508)
- 978 — North-central and northeastern Massachusetts (Lowell, Lawrence, Haverhill, Fitchburg)
- 351 — North-central and northeastern Massachusetts (overlay of 978)
How Boston’s Area Codes Grew Over Time
Boston received its first area code, 617, when the North American Numbering Plan launched in 1947. That single code initially covered the entire state, and subsequent splits and overlays narrowed it over the decades that followed.
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Browse Boston Area Codes →- 1947 — 617 assigned in October 1947 as one of the original North American area codes, covering the eastern two-thirds of Massachusetts including Boston, from western Worcester County to Cape Cod and the South Coast.
- 1988 — 508 split off from 617 on July 16, 1988, taking the northern, western, and southern portions of the old 617 territory and leaving a semicircle around Boston in 617. Permissive dialing continued until January 1, 1989.
- 1997 — 978 split off from 508 on September 1, 1997, taking the northern part of the 508 service area in north-central and northeastern Massachusetts.
- 1997 — 781 split off from 617 on September 1, 1997, taking the suburbs surrounding Boston along the Route 128 corridor and leaving 617 largely coextensive with the inner ring of Greater Boston.
- 2001 — 857, 339, 774, and 351 all activated on May 2, 2001, as overlays of 617, 781, 508, and 978 respectively. Ten-digit dialing became mandatory across eastern Massachusetts.
Why Boston Has Multiple Area Codes
A single area code can hold roughly 7.9 million possible phone numbers in theory — 792 valid central office codes (the second three digits) multiplied by 10,000 line numbers each. In practice the usable count is lower, because blocks of numbers are reserved, withheld, or assigned in bulk to carriers that may never fully use them. When the pool of available numbers in an area code falls below the threshold the North American Numbering Plan Administrator (NANPA) tracks, the state requests relief, and either a split or an overlay is approved.
Boston’s population of roughly 5,025,517 residents would, on its own, fit comfortably inside a single area code’s capacity. The reason 8 codes are needed instead is that every adult typically carries at least one mobile line, many households have multiple lines per person, businesses concentrate phone numbers at extreme density, and connected devices, VoIP services, and second-line apps all draw from the same pool. The math compounds quickly.
Boston Area Codes by District
City of Boston and inner communities (617, 857): Boston proper plus Brookline, Cambridge, Newton, and Quincy. 617 is the original from 1947; 857 was added as an overlay in 2001.
Route 128 corridor and South Shore suburbs (781, 339): Boston's inner suburbs including Waltham, Woburn, Lynn, Weymouth, and Dedham. 781 split off from 617 in 1997; 339 overlay added in 2001.
South-central and southeastern Massachusetts (508, 774): Worcester, Framingham, Brockton, Fall River, and New Bedford. 508 split off from 617 in 1988; 774 overlay added in 2001.
North-central and northeastern Massachusetts (978, 351): Lowell, Lawrence, Haverhill, and Fitchburg. 978 split off from 508 in 1997; 351 overlay added in 2001.
What’s Next for Boston Area Codes
Greater Boston’s numbering pool has been stable since the four overlays activated in 2001, and no relief activity is currently planned for any of the metro’s numbering plan areas. NANPA’s October 2025 NPA exhaust analysis projects the core 617/857 complex serving the city of Boston will not exhaust until 2059, and the surrounding 781/339, 508/774, and 978/351 complexes carry similarly long runways. The 2001 decision to add overlays rather than split territory means existing numbers have kept their area codes, with new lines drawn from the overlay code in each region.
Frequently Asked Questions
How many area codes does Boston have right now?
Boston has 8 active area codes in service across the territory it covers, including any overlays that share geography with an older code.
What is the oldest area code in Boston?
617 is the oldest active area code in Boston, assigned in 1947 when the North American Numbering Plan launched. It remains in service today, though its geographic footprint has typically been reduced by subsequent splits and overlays.
What is the newest area code in Boston?
The most recent area code addition to Boston was 857, activated in 2001. New phone lines provisioned in its service area are increasingly drawn from this code as older overlays approach exhaustion.
Why does Boston need so many area codes?
Population growth combined with the proliferation of mobile lines, business direct-dial numbers, VoIP services, and connected devices has exhausted older codes faster than the original 1947 plan anticipated. Each new area code adds roughly 7.9 million additional phone numbers to the regional pool.
How many area codes does Boston have?
The Boston metropolitan area is served by eight area codes across four overlay complexes: 617 and 857 for the city and inner communities, 781 and 339 for the Route 128 suburbs and South Shore, 508 and 774 for south-central and southeastern Massachusetts, and 978 and 351 for the northern suburbs. The city of Boston itself uses 617 and 857.
What is the original Boston area code?
617 is the original Boston area code, assigned in October 1947 as one of the first North American area codes. It once covered the entire eastern two-thirds of Massachusetts before successive splits in 1988 and 1997 narrowed it to the city of Boston and its closest communities such as Brookline, Cambridge, Newton, and Quincy.
What is the difference between 617 and 857?
There is no geographic difference. 857 is an overlay of 617, meaning both codes serve the exact same area, the city of Boston and its inner communities. 617 is the original code dating to 1947; 857 was added in 2001 to provide more numbers. Ten-digit dialing is required for both.
Why does the Boston area need so many area codes?
Demand for phone numbers in eastern Massachusetts outpaced the supply within a single code several times. 617 was split into 508 in 1988 and 781 in 1997, and 508 was split into 978 in 1997. When all four resulting regions neared exhaustion again in 2001, regulators added overlay codes (857, 339, 774, and 351) rather than splitting territory further, so existing customers could keep their numbers.
Ready to Get a Number in Boston?
We carry available Boston numbers right now across multiple area codes. Order directly in 617, 339, 351, 508, or 774 — a one-time fee, no monthly charges, with pricing From $150 depending on the digit pattern and memorability of the number. Prefer help choosing? Call us at (212) 580-2000.
Related Reading
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