631 area code — Brentwood, NY geographic
Area code 631 is a geographic code serving Brentwood, New York in the Eastern time zone. It has been in service since November 1, 1999. The same territory is also served by its overlay code (631/934 complex). Keep in mind the code identifies where the number was registered; the person calling may be elsewhere.
The code currently holds 782 working prefixes, held by 39 different carriers. Of these, 600 are pooled prefixes shared by multiple carriers. Numbers are anchored to 54 rate centers — billing localities that fix where each prefix belongs.
The code was carved out of 516 (1999). As demand grew it in turn gave rise to 934 (2016).
The current NANPA exhaust forecast for the 631/934 complex is 3Q 2079.
Local calls inside 631 are dialed 10D; 1+10 digit permissible at service provider discretion.
To check where a specific 631 number was issued, look up its six-digit prefix; to check who is actually calling, ignore the display and verify through an official callback number — caller ID is assertable and routinely spoofed.
Largest localities in 631
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Brentwood | 127 | 516, 934 |
| Farmingdale | 42 | 363, 516, 934 |
| Riverhead | 40 | 934 |
| Huntington | 34 | 934 |
| Central Islip | 32 | 516, 934 |
| Amityville | 31 | 516, 934 |
| Babylon | 28 | 934 |
| Deer Park | 27 | 934 |
| Patchogue | 26 | 934 |
| Ronkonkoma | 24 | 934 |
FAQ
Why am I getting spam calls from 631 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 631 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 631 number from?
631 is assigned to Brentwood and surrounding areas of New York in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.
Is 631 a toll-free number?
No. 631 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.
Why do 934 and 631 cover the same place?
They are overlays: when a code runs low on numbers, a new code is added over the same territory instead of splitting it. The 631/934 complex shares one service area, and local calls are dialed with 10 digits.
Will 631 run out of numbers?
NANPA's current forecast projects exhaust in 3Q 2079 — decades of capacity remain.