603-780 phone numbers

Numbers 603-780-0000 to 603-780-9999 are assigned to Level 3 Communications, LLC in Canaan, NH.

Not assigned to any carrier: 603-780-0xxx, 603-780-1xxx, 603-780-2xxx, 603-780-3xxx, 603-780-5xxx, 603-780-6xxx, 603-780-7xxx, 603-780-8xxx, 603-780-9xxx — calls from these use spoofed caller IDs.

Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.

Reported numbers in 603-780