The area code 203 is located in Bridgeport, Connecticut.
Area code 203 serves Bridgeport, Connecticut and much of southwestern Connecticut along Long Island Sound, covering key communities in Fairfield and New Haven counties. Centered on Bridgeport—the state’s largest city—it follows the busy I-95 and Metro-North corridors, connecting coastal towns and major employers. If you see a 203 phone number, it typically traces back to this region, which blends urban hubs, historic neighborhoods, and waterfront access.
“Area code 203 was one of the original North American area codes created in 1947.” — North American Numbering Plan Administration (NANPA)
First assigned in 1947 to the entire state, 203 was reduced in 1995 when area code 860 split off to serve northern and eastern Connecticut. To add more numbers without changing existing ones, the 475 overlay joined 203 in 2009, and the region now uses mandatory 10-digit dialing for local calls. Today, area code 203 (and overlay 475) supports both landlines and mobile phones across this dynamic stretch of Connecticut, from Bridgeport’s busy port to the university and biotech centers around New Haven, and the financial hubs of Stamford and Greenwich.