Area code 667 is the second overlay for Maryland’s 410 and 443 area codes, covering eastern Maryland, including Baltimore, Annapolis, and surrounding areas. It was introduced in 2012 due to continued demand for phone numbers in the growing Baltimore metro area. The implementation of 667 ensures that residents and businesses have access to new numbers while maintaining continuity across the region. Ten-digit dialing is mandatory, and 667 is typically seen on newer mobile phones and VoIP services. While it doesn’t carry the legacy recognition of 410 or 443, 667 is an essential part of the state’s modern telecommunications infrastructure.