Area code 603

In 2011, area code 603 was said to be nearing exhaustion and a second area code for New Hampshire was expected to be activated by 2013 as a statewide overlay plan. As a result of changes in allocation policies and a reclamation of a large block of previously allocated telephone numbers, including number pooling, the exhaustion time frame has been moved to at least 2032.

Ten-digit dialing

Prior to October 2021, area code 603 had telephone numbers assigned for the central office code 988. In 2020, 988 was designated nationwide as a dialing code for the National Suicide Prevention Lifeline, which created a conflict for exchanges that permit seven-digit dialing. This area code was therefore scheduled to transition to ten-digit dialing by October 24, 2021.