Area Code 857

About Area Code 857

Area code 857 is a geographic telephone area code assigned to Boston, Massachusetts. It operates in the Eastern time zone and was first introduced in 2001. Overlay for 617. Boston metro.

Within Massachusetts, area code 857 shares numbering capacity with 8 other area codes. The state's 7,100,960-person population (2023 Census Bureau estimate) is served by a combined 9 active codes, with 857 primarily responsible for the Boston region. Massachusetts's state capital is Boston, and its largest city is Boston.

When you receive a call from a 857 number on your Caller ID, the call originated from a phone number assigned to the 857 area code — but be aware that Local Number Portability (in effect since 2003) means the caller could be physically located anywhere in the US or Canada. Area code 857 only confirms where the number was originally assigned.

Where is the 857 area code located?

Area code 857 is assigned to Boston, Massachusetts, in the Eastern time zone. The state of Massachusetts uses 9 active area codes, and 857 is one of them. Calls placed from the 857 area code originate from numbers assigned by NANPA — the North American Numbering Plan Administrator — and the 857 prefix appears on Caller ID for both landline and wireless calls placed from this region.

The Eastern time zone observes Daylight Saving Time, shifting from UTC-5 to UTC-4 in summer. The local time shown above is always current, so you can quickly check whether it's a reasonable hour to call back.

What cities and counties use the 857 area code?

The 857 area code serves 10 notable cities, listed below in order of population. The largest city in the 857 territory is Boston (651,092 residents in Suffolk County).

• Boston, MA — 651,092 residents (37.3% of 857 numbers)
• Worcester, MA — 207,621 residents (11.9% of 857 numbers)
• Springfield, MA — 155,927 residents (8.9% of 857 numbers)
• Cambridge, MA — 118,927 residents (6.8% of 857 numbers)
• Lowell, MA — 114,790 residents (6.6% of 857 numbers)
• Brockton, MA — 105,451 residents (6% of 857 numbers)
• Quincy, MA — 101,728 residents (5.8% of 857 numbers)
• Lynn, MA — 101,993 residents (5.8% of 857 numbers)
• Fall River, MA — 94,449 residents (5.4% of 857 numbers)
• New Bedford, MA — 95,363 residents (5.5% of 857 numbers)

Phone number format in area code 857

All phone numbers within area code 857 follow the standard North American 10-digit format:(857) NXX-XXXX. The NXX is the central office prefix (also called an "exchange") and XXXX is the subscriber line number. For long-distance calls within the NANP, dial 1 + 857 + NXX + XXXX. From outside North America, dial your country's international access code, then 1 (the NANP country code), then the 10-digit number.

If you need to verify whether a specific 857 number is wireless, landline, or VoIP, you can use our reverse phone lookup tool. Be aware that number portability means the area code no longer guarantees the caller's physical location — only where the number was first assigned.

History of area code 857

Overlay for 617. Boston metro.

The original 86 area codes were assigned by AT&T and Bell Labs in 1947 as part of the North American Numbering Plan. At the time, rotary-dial phones meant codes with lower digits (like 212 for NYC, 213 for LA, 312 for Chicago) were given to the largest cities because they took less time to dial. Today's area code assignments still reflect those early choices, even though touch-tone and cell phones made the original reason obsolete.

Is the 857 area code safe to answer?

Area code 857 itself is a normal geographic code with no elevated spam risk. That said, scammers can spoof any area code — including 857 — so if you don't recognize the full number, let it go to voicemail and verify the caller's identity before calling back.