Area Code Atlas

Overlay of 959 announced for 860

Area code 959 was announced in August 1999 as an overlay for the 860 region due to continued growth in demand for telephone numbers. Implementation was delayed for over a decade because of number allocation changes.

Update on the Introduction of NPAs 475 and 959 (Connecticut)

Mandatory ten-digit dialing implemented for all Connecticut area codes

On November 14, 2009, mandatory ten-digit dialing was implemented statewide in Connecticut in preparation for the 475 overlay on 203 and the planned 959 overlay on 860. This change was part of the broader transition involving area codes 203, 475, 860, and 959, supporting the introduction of new overlay codes, including 959 for the 860 region.

NPA 959 overlay on 860 announced

NPA 959 to Overlay NPA 860 (Connecticut)

NANPA issues Planning Letter 456 for 959 overlay

NANPA issued Planning Letter 456 on August 27, 2013, announcing the in-service date for area code 959 as August 30, 2014, to overlay the 860 region.

NPA 959 overlays 860

Area code 959 was implemented as an overlay for 860 in 2014, providing additional numbering resources for most of Connecticut outside the southwestern region.

Activation of 959 overlay on 860

On August 30, 2014, area code 959 was activated as an overlay on the 860 region of Connecticut, providing additional numbering resources for most of Connecticut outside the southwest. The new code was introduced to address the exhaustion of available numbers in the 860 area, with both codes serving the same geographic region. New telephone numbers in the region could be assigned either the 860 or 959 area code.