ZIP codes
247
Area Code 603
Explore ZIP codes in area code 603 — covering ME, NH — 247 ZIP codes — 1,387,907 residents. Population, income, and housing at a glance.
Population
1,387,907
States
ME, NH
Median household income (avg.)
$98,133
Average home value
$364,137
Where is area code 603?
Area code 603 maps to 247 indexable ZIP codes on US5 across ME and NH, with a combined ZIP-area population of about 1,387,907.
Among places with the most population in this NPA on US5 are Manchester, NH, Nashua, NH, Concord, NH, Derry, NH, and Dover, NH. Open any ZIP below for full demographics, housing, and nearby services.
The most populous ZIP currently listed for 603 is 03103 (about 37,659 residents).
Income and housing in 603
Across ZIPs with income data in area code 603, the average median household income is about $98,133 — about 31% above the U.S. median ($75,149).
Average median home value across those ZIPs is about $364,137.
On this page’s income ranking, ZIP 03750 is near the top at about $218,750.
How area code 603 numbering works
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 603 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 603, and overlays or split NPAs can mean multiple area codes serve the same metro.
Scams and caller ID spoofing
Seeing area code 603 on caller ID does not prove the caller is physically in ME and NH. 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.
ZIP codes in area code 603
Frequently asked questions
Where is area code 603?
Area code 603 is associated with ZIP codes in ME and NH on US5, covering about 1,387,907 combined ZIP-area residents across 247 codes. Browse the ZIP table on this page for cities and counties.
How many ZIP codes are in area code 603?
US5 currently lists 247 indexable ZIP codes for area code 603. Counts can change as geography publishes update.
What is the average income in area code 603?
The average of ZIP median household incomes in area code 603 is about $98,133 (about 31% above the U.S. median ($75,149)). Individual neighborhoods vary — sort the ZIP table by income to compare.
What is an NXX or “number block” in area code 603?
After the area code, the next three digits (NXX) identify a central office / exchange “block” of up to 10,000 numbers. US5 focuses on ZIP geography for 603; for live number assignment details, use official NANPA / carrier resources.
Does a 603 caller ID mean the person is local?
No. Caller ID can be spoofed to show area code 603 even when the caller is elsewhere. Treat unexpected calls about money, arrests, or account lockouts as suspicious and verify through official channels.
How can I avoid phone scams that use area code 603?
Do not trust caller ID alone. Never send gift cards, wire money, or install remote-access apps because a caller claims to be from the IRS, a bank, or tech support. Hang up and call back using a published number from a statement or official website.
What cities use area code 603?
Larger population clusters on US5 for 603 include Manchester, NH, Nashua, NH, Concord, NH, Derry, NH, and Dover, NH. Open linked ZIP pages for neighborhood-level demographics.