603 area code — Manchester, NH geographic

Data: NANPA public reports, current as of July 28, 2026.

Area code 603 is a geographic code serving Manchester, New Hampshire in the Eastern time zone. It has been in service since January 1, 1947. Note that porting and VoIP mean a 603 number can be used from anywhere — the code marks where the number was assigned.

752 central-office prefixes are currently active in this code, spread across 49 code-holding carriers. Thousands-block pooling applies to 601 prefixes, so a single prefix can belong to several carriers. Its prefixes map to 147 distinct rate centers.

NANPA projects numbering capacity to exhaust in 4Q 2040.

Dialing: 10D locally, 1+10D to other codes (1+10 digit permissible at service provider discretion.).

Worth noting: 603 is the only area code serving New Hampshire.

Use this page to decode where 603 numbers come from — and remember that spoofing means the screen can lie about everything except your own caution.

Largest localities in 603

FAQ

Where is a 603 number from?

603 is assigned to Manchester and surrounding areas of New Hampshire in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.

Is 603 a toll-free number?

No. 603 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.

Will 603 run out of numbers?

NANPA's current forecast projects exhaust in 4Q 2040 — decades of capacity remain.

Why am I getting spam calls from 603 numbers?

Scammers spoof recognizable area codes so calls look local or familiar. A displayed 603 number does not prove the call originated there — see our guide to spotting spoofed calls.