Area codes 860 and 959

Area codes 860 and 959 are telephone area codes in the North American Numbering Plan for the U.S. state of Connecticut. They are arranged in an overlay complex for a numbering plan area (NPA) that comprises most of the state, except its southwest, which uses area codes 203 and 475.

Connecticut state map with area code 860 in red

Area code 860 was created on August 28, 1995 in an area code split of the 203 NPA, in which the latter was reduced to Fairfield County (except for Sherman) and New Haven County, plus part of Litchfield County (Bethlehem, Woodbury, and a small part of Roxbury). Dialing of area code 860 became mandatory on October 4, 1996.

Area code 959 was originally announced in August 1999 to overlay area code 860, but implementation was delayed for over a decade, culminating in an in-service date of August 30, 2014. Nevertheless, all calls within Connecticut required ten-digit dialing as of November 14, 2009.

1999 overlay proposal

Within less than five years, 860 was already facing exhaustion due to the proliferation of cell phones, pagers, and dial-up Internet. In August 1999, the Connecticut Department of Public Utility Control proposed to overlay 860 with the new area code 959. The alternative would have been a split that would have seen some Connecticut residents having to change their numbers for the second time in a decade.

The implementation of the proposed overlay was postponed for nearly a decade due to number conservation measures. By September 2008, the need for an overlay could no longer be staved off. That month, implementation of 959 was scheduled within two years. In March 2009, it was announced that the 203/475 overlay would be activated on December 12, 2009, with the 860/959 overlay becoming active by 2011.

Even though the 959 area code did not have a specific start date, ten-digit dialing became mandatory in all of Connecticut on November 14, 2009. As of that date, a leading 1 was required for originating toll calls from landlines to reach another Connecticut number, including calls involving two numbers with the same area code.

On August 27, 2013, the NANPA issued Planning Letter 456 which states that the 959 area code would go into effect on August 30, 2014.^[1] The first 959 area code numbers were distributed in December 2015.^[2]

Major cities and towns

• Bloomfield
• Bristol
• East Hartford
• East Lyme
• Enfield
• Glastonbury
• Groton
• Hartford
• Litchfield
• Manchester
• Middletown
• New Britain
• New London
• New Milford
• Norwich
• Old Lyme
• Sherman
• Southington
• Storrs
• Stonington
• Torrington
• West Hartford
• Willimantic
• Windsor