Area Code 203 — Hartford, CT
Area code 203 serves Hartford and New Haven in Connecticut. It is a geographic code in the Eastern Time time zone and is overlaid by 475.
Quick facts for area code 203
What is area code 203 and where does it cover?
Area code 203 serves southwestern Connecticut, covering much of Fairfield County, all of New Haven County, and a small part of Litchfield County - including Bridgeport, New Haven, Stamford, Waterbury, Norwalk, Danbury, Greenwich, and Westport. It is overlaid by 475, so new numbers in the same footprint may be assigned 475. Ten-digit dialing is required. 
How did area code 203 evolve over time?
- 1947: Connecticut received original code 203 statewide under the first NANP.
- 1995: State split; 860 created for the rest of Connecticut, leaving 203 in the southwest.
- 2009: Overlay 475 added to 203; permissive dialing preceded statewide 10-digit dialing.
These changes responded to number demand from population growth and mobile devices. 
What are the current dialing rules for 203/475?
Since late 2009, 10-digit dialing is mandatory for local calls across Connecticut, including the 203/475 region. This change prepared for the 475 overlay (and later 959 over 860). Existing 203 numbers did not change. 
Which cities and communities are most associated with 203?
Major communities include Bridgeport, New Haven, Stamford, Norwalk, Waterbury, Danbury, Greenwich, Fairfield, West Haven, Milford, Hamden, and Shelton—core parts of the Connecticut segment of the New York metro area. 
What interesting facts are tied to 203?
- One of the original NANP area codes (1947): 203 is among the early U.S. codes assigned when nationwide direct dialing launched. 
- Statewide 10-digit dialing came with 203’s overlay era: Connecticut moved the entire state to 10-digit dialing in November 2009, a notable early statewide switch. 
What time is it in area code 203 right now?
Hartford
Connecticut
Current Location
Major Cities in 203
Here are notable cities served by this area code. Click through for local details.
Overlay area codes for 203
These overlay codes share geography with area code 203 and typically require ten-digit dialing.
Other Area Codes in Connecticut
Select a region to see every area code assigned there.
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Popular: 867
Legacy toll-free code. Variants include 888, 877, 866, 855, 844, 833, 822.
View detailsFrequently asked questions about area code 203
Which cities does area code 203 serve?
Open the Major Cities and Quick Facts sections on this page for communities covered by 203, including overlays when they apply.
Does area code 203 use an overlay?
An overlay adds one or more new area codes to the same geography so existing numbers keep their code while new numbers may get a different one—ten-digit dialing is usually required.
How do I search phone numbers in area code 203?
Use the search box on this page or PhoneNumbers.com search, then filter by area code, city, or state to browse available numbers.