Area Code 203

Area code 203 maps to 88 indexable ZIP codes on US5 across CT, with a combined ZIP-area population of about 1,830,804.

Among places with the most population in this NPA on US5 are New Haven, CT, Stamford, CT, Bridgeport, CT, Waterbury, CT, and Norwalk, CT. Open any ZIP below for full demographics, housing, and nearby services.

The most populous ZIP currently listed for 203 is 06902 (about 72,915 residents).

Across ZIPs with income data in area code 203, the average median household income is about $121,745 — about 62% above the U.S. median ($75,149).

Average median home value across those ZIPs is about $536,394.

On this page’s income ranking, ZIP 06820 is near the top at about $250,001.

In the North American Numbering Plan, the first three digits of a 10-digit phone number are the Numbering Plan Area (NPA), commonly called the area code. Digits 4–6 are the central office code (NXX / “exchange”), and the last four digits identify the individual line.

US5’s 203 page groups ZIP codes that are associated with this NPA in published geography data. That is a place-based view — it is not a live directory of every phone number assigned to 203, and overlays or split NPAs can mean multiple area codes serve the same metro.

Seeing area code 203 on caller ID does not prove the caller is physically in CT. Spoofing tools can display almost any NPA, including local-looking numbers used in IRS, bank, warranty, and “grandparent” scams.

If you receive an unexpected call about taxes, arrests, or locked accounts: hang up, do not share codes or remote-access software, and contact the organization using a number from its official website or your statement — not a number the caller provides. US5 publishes geography for research; it does not verify live callers.