203 Area Code
The 203 area code is a long-established telephone code in the United States that serves southwestern Connecticut. Created in 1947 as part of the original North American Numbering Plan (NANP), 203 originally covered the entire state of Connecticut; today it focuses on the lower Fairfield County and New Haven County corridors. Numbers beginning with 203 are commonly associated with cities such as New Haven, Bridgeport, and Stamford, and they remain widely used by businesses, colleges, medical centers, and residents in the region.
Understanding the 203 Area Code
The 203 area code identifies phone numbers located in the southwestern portion of Connecticut. Because demand for new numbers grew, the 475 overlay was added to the same geographic area; both codes serve the same communities. The common telephone format is (203) NXX-XXXX (or (475) NXX-XXXX for overlay numbers). For all local dialing within the overlay region, 10-digit dialing (area code + 7-digit number) is required.
203 Area Code Map and Geographic Location
The 203 area code map covers southwestern Connecticut - the coastal corridor along Long Island Sound and the adjacent inland suburbs. On an interactive map, the 203/475 region includes the cities and towns lining the I-95 and Merritt Parkway corridors from the New York state line east through Fairfield County into New Haven County and portions of western Connecticut. This area forms part of the New York City and New England commuting and business region.
All Major Cities and Areas in the 203 Area Code Region
The 203/475 telephone zone includes many of Connecticut's most populous cities and suburban communities. Major centers and municipalities include:
- New Haven County: New Haven, Hamden, Milford, West Haven, North Haven, Branford, Guilford
- Fairfield County: Bridgeport, Stamford, Norwalk, Danbury, Fairfield, Stratford, Shelton, Trumbull, Ridgefield
ZIP Codes within the 203 Telephone Zone (Examples)
ZIP codes overlap the 203/475 area; here are representative examples by city:
- New Haven - 06510, 06511, 06513
- Bridgeport - 06604, 06605, 06606
- Stamford - 06901, 06902, 06905
- Norwalk - 06851, 06854
- Danbury - 06810, 06811
- Waterbury (adjacent parts) - 06702, 06706
- Milford - 06460
- Stratford - 06615
- Shelton - 06484
- Fairfield - 06824
Time Zone
The 203 area code is in the Eastern Time Zone (ET). It observes Eastern Standard Time (EST, UTC-5) in the winter and Eastern Daylight Time (EDT, UTC-4) during daylight saving time, matching the schedule used by major East Coast cities.
Dialing, Phone & Service Details
- Local dialing: Because 203 shares its geography with overlay 475, callers must use 10-digit dialing (area code + 7-digit number) for all local calls.
- Long-distance (within NANP): Dial
1 + area code + numberfor calls outside the local calling area. - International: From abroad, dial your international exit code +
1(USA country code) +203+ the 7-digit number (for example:+1 203 555 0123). - Services: 203 and 475 numbers are used for landlines, mobile phones, VoIP, business PBX systems, emergency services, educational institutions (for example, regional colleges and hospitals), and government lines.
Why the 203 Area Code Matters
The 203 number signals a southwestern Connecticut presence - a region with strong ties to finance, healthcare, education, manufacturing, and transportation networks connecting New York City and New England. Universities, major hospitals, local media, and corporate offices often use 203 numbers to emphasize local access and credibility. For residents and businesses, 203 provides reliable local identity and integration with regional mapping, delivery, and emergency services.
What area code is 203? / Where's area code 203?
What area code is 203? - 203 is a telephone area code serving southwestern Connecticut, primarily New Haven and Fairfield counties.
Where's area code 203? - It covers the coastal and near-coastal communities of southwestern Connecticut, including cities such as New Haven, Bridgeport, Stamford, Norwalk, Danbury, Milford, and surrounding towns.
Frequently Asked Questions (FAQ) about 203 Area Code
What cities are covered by area code 203?
Major cities include New Haven, Bridgeport, Stamford, Norwalk, Danbury, Milford, Stratford, and many surrounding towns in New Haven and Fairfield counties.
When was the 203 area code created?
203 was created in 1947 as one of the original NANP area codes. Over the decades its coverage narrowed as Connecticut was split into additional area codes; the 475 overlay was added later to provide more numbers.
Do I need to dial 10 digits for 203 numbers?
Yes. Because 203 shares its geographic area with overlay code 475, 10-digit dialing (area code + 7-digit number) is mandatory for local calls.
How do I call a 203 number from outside the U.S.?
Dial your international exit code, then +1 203, followed by the seven-digit local number (for example: +1 203 555 0123).
Is 203 a cell phone or landline area code?
Both. The 203/475 region assigns numbers to mobile phones, landlines, VoIP providers, and businesses.
