← Area code 603
603-784 phone numbers
Numbers 603-784-0000 to 603-784-9999 are assigned to Mcimetro Access Transmission Services LLC (rate centre PETERBROGH, NH, NANPA abbreviation). 3 of its ten thousand-number blocks are assigned to other carriers (number pooling).
Not assigned to any carrier: 603-784-0xxx, 603-784-1xxx, 603-784-3xxx, 603-784-6xxx, 603-784-7xxx, 603-784-8xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.