Connecticut is in the midst of its transition from two area codes to four, as the number combinations in 203 and 860 are nearly all used, less than 20 years after the 860 area code was introduced into the state. In the 203 area code, which covers the southern portion of the state, area code 475 has been designated as the overlay for that region, to be used for new service. For the northern part of the state, now utilizing area code 860, the overlay area code to be used as new phone numbers are assigned will be 959 (start date to be determined).
In 1947, U.S. states and Canadian provinces were assigned three digit codes with 0 as the middle number, such as 203 for Connecticut and 305 for Florida . The 860 area code was created on August 28, 1995 as a split from area code 203 when the latter was cut back to Fairfield County (except for the Town of Sherman) and New Haven County, plus the towns of Bethlehem, Woodbury, and a small part of Roxbury in Litchfield County.
Use of 860 began almost 50 years after the assignment of 203 - on October 4, 1996. The ever-increasing number of devices requiring phone numbers in the 21st century has accelerated the need for additional area codes. While it took nearly 50 years to move from one area code to two, it is expected to take less than 20 years to move from two to four.
Back in 1947, there were 86 area codes in North America. States and provinces that had more than one area code distributed to them were given three digit codes with 1 as the middle number, such as 916 and 213 for various sections of California , and 212 and 516 for various sections of New York . The first and third digits were allotted according to population density in the city or region the area code was going to, with the most populated areas getting the lowest numbers. The New York City area, for example, was assigned 212, while the surrounding suburbs were assigned 914.
The rationale for the original “low number/high population” scheme was based on the fact that phones had rotary dials in those days. Lower numbers resulted in shorter “dial pulls” so it was reasoned that the regions with the most people in them should require the least “work” to call.