Area code 203 is one of the original codes established in 1947 and serves southwestern Connecticut, including cities such as Bridgeport, New Haven, Stamford, and Norwalk. It was the only area code in Connecticut until 1995, when 860 was created to serve the rest of the state. In 2009, 203 was overlaid with area code 475, making ten-digit dialing mandatory across the region. The 203 area is known for its proximity to New York City and its affluent suburban communities, as well as major educational institutions like Yale University. The area is a mix of industrial history, academic prestige, and financial prosperity. Despite the overlay, 203 remains a highly recognizable and preferred area code for businesses and residents in the region.