Area Code 551 — Newark, New Jersey

NANP area code

551

UTC−5, UTC−4 during daylight saving

State
New Jersey
Primary city
Newark
Time zone
Eastern
In service
2001
Overlay
201

The code reaches 85 communities and 7 counties across New Jersey.

Was this call legitimate?

The area code itself carries no risk signal. 551 is assigned to Newark, New Jersey, so a call from it is consistent with a real caller in that area — but the digits alone prove nothing, because they can be forged.

Caller ID is set by whoever places the call, not verified by the network. That is why neighbour spoofing works: an operation anywhere in the world can display a number that matches the area code — and often the first three digits after it — of the person being called, so the call looks local. Every community in the 551 territory is a plausible-looking origin for a forged 551 number, which is why one can be made to look like a neighbour to so many people. The same applies to its overlay code 201, which serves the same ground.

If you did not recognise the call: let it go to voicemail — a legitimate caller with real business will leave one. Do not return the call using the number shown; look the organisation up independently and call the number you found. Never confirm personal details, card numbers, or one-time codes to someone who called you, however plausible the number looked.

Codes.zone publishes no complaint counts, risk scores, or caller identities. We hold no data on individual numbers and will not estimate what we cannot source.

Local time and when to call back

Time there now

Eastern · UTC−5, UTC−4 during daylight saving

Reasonable callback window

8:00 AM – 9:00 PM

local time in Eastern

Federal rules bar telemarketing calls to a residence outside 8:00 AM–9:00 PM in the called party's own time zone. It is a sensible bound for a personal callback too — and a caller who rang you well outside it was not observing it.

Overlay codes and ten-digit dialling

551 does not have its territory to itself. 201 covers the same ground, serving Newark and the rest of the 551 territory. An overlay is what a regulator adds when a region runs out of assignable numbers: rather than splitting the area and forcing half the residents to change their number, a second code is laid over the top and new numbers are issued from it.

The practical consequence: two neighbours on the same street can hold numbers in different area codes, so the code tells you nothing about which part of town a caller is in — and local calls must be dialled as all ten digits, because seven is no longer unambiguous.

Cities served

largest 20 by ZIP count
Communities served by area code 551, ranked by how many ZIP codes each holds.
CityZIP codesCounty
Newark20Essex County
Jersey City12Hudson County
Morristown3Morris County
Caldwell2Essex County
Hackensack2Bergen County
Kearny2Hudson County
Mahwah2Bergen County
Paramus2Bergen County
Ridgewood2Bergen County
Secaucus2Hudson County
Summit2Union County
Teterboro2Bergen County
Wayne2Passaic County
Allendale1Bergen County
Alpine1Bergen County
Bayonne1Hudson County
Bergenfield1Bergen County
Bogota1Bergen County
Butler1Morris County
Carlstadt1Bergen County

65 further communities not listed. All New Jersey area codes →

Each point is a community served by 551, plotted from its record coordinates. The outline is the convex envelope of those points — a footprint, not a boundary.
  • Reference points and footprint
  • Not an official NANPA boundary
  • Not a USPS delivery area

Scope every community matched to 551. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot), GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated . Coordinates are place reference points, not boundaries.

Counties

Prefixes inside 551

We do not publish the NXX prefixes inside 551. The assignment of prefixes to rate centres comes from LERG routing data, which is proprietary, and we will not estimate it from postal data — ZIP codes and telephone prefixes do not map onto each other. Awaiting a clean-rights NPA-NXX source.

Why this code exists

551 is the newer code here, added in 2001 over 201 (1947). The older code had run out of exchanges to assign, and an overlay avoids the alternative — splitting the region and forcing half its residents to renumber. New lines have been issued from 551 since.