← Area code 534
534-421 phone numbers
Numbers 534-421-0000 to 534-421-9999 are assigned to Level 3 Communications, LLC in Marengo, WI.
Not assigned to any carrier: 534-421-0xxx, 534-421-1xxx, 534-421-2xxx, 534-421-3xxx, 534-421-4xxx, 534-421-5xxx, 534-421-6xxx, 534-421-8xxx, 534-421-9xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.