Area codes 860 and 959

They are arranged in an overlay plan that covers most of the state, except its southwest, which uses area codes 203 and 475.

Area code 860 was created on August 28, 1995, as a numbering plan area split from area code 203, 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).

Area code 959 was originally announced in August 1999 to overlay area code 860, but implementation efforts were delayed for over a decade, culminating in an effective starting date for operation of August 30, 2014.

This proposal was postponed for nearly a decade due to number conservation measures; in September 2008, the overlay was scheduled within two years (as of August 30, 2011, an activation date for 959 had not been announced).

A leading 1 is required for originating toll calls from landlines, effective November 14, 2009, to reach another Connecticut number, including calls involving two numbers with the same area code.