Michigan Area Code 679

Published: July 14, 2023

Estimated to soon run out of assignable central office codes, Detroit's Numbering Plan Area 313 will, from November 2025, get a new overlay NPA. The new 679 area code will serve the same geographic area currently served by area code 313: the city of Detroit and surrounding Wayne County suburbs. As with all areas served by two or more overlaying area codes, 7 digit dialing will no longer be possible.

Key dates

• April 7, 2025 - permissive 7/10 digit dialing begins (local calls within NPA 313 borders may be dialed using 7 or 10 digits)
• October 7, 2025 - 10 digit dialing becomes mandatory
• November 7, 2025 - new area code 679 enters service

See official NANPA announcement and rate center map of the new overlay complex 313/679 (PDF document).