Area codes in Trenton, New Jersey
Trenton, New Jersey uses 2 area codes — 609 and 640. The main Trenton area code is 609.
Area codes serving Trenton
Phone numbers in Trenton are written as ten digits — for example (609) 555-0190 — and fall in the Eastern Time zone.
How Trenton came to have 2 area codes
The original Trenton area code is 609, in service since 1957. As the area ran low on available numbers, an overlay code was added over the same region for new phone lines: 640 (2018). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Trenton now uses all 2 codes and every local call is dialed with ten digits.
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Nearby cities
- New Brunswick area codes
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- Toms River area codes
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- Staten Island area codes
More cities in New Jersey
- Newark area codes
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- Hoboken area codes
- Paterson area codes
- Clifton area codes
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Frequently asked questions
What is the area code for Trenton?
The main area code for Trenton, New Jersey is 609. Trenton is now served by 2 area codes in total: 609, 640.
How many area codes does Trenton have?
Trenton has 2 area codes: 609, 640.
Why does Trenton have more than one area code?
As Trenton used up the numbers available in its original area code (609, in service since 1957), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a Trenton number?
Dial all 10 digits — the area code (609 or 640) followed by the 7-digit local number. From abroad, dial +1, then the area code and number.
Sourced from the official NANPA (North American Numbering Plan Administrator) numbering database, current as of August 2, 2026. Refreshed monthly.