Area Code 227 — Baltimore, Maryland

NANP area code

227

UTC−5, UTC−4 during daylight saving

State
Maryland
Primary city
Baltimore
Time zone
Eastern
In service
2023
Overlays
240, 301

The code reaches 217 communities and 14 counties and independent cities across Maryland.

Was this call legitimate?

The area code itself carries no risk signal. 227 is assigned to Baltimore, Maryland, 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 227 territory is a plausible-looking origin for a forged 227 number, which is why one can be made to look like a neighbour to so many people. The same applies to its overlay codes 240 and 301, which serve 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

227 does not have its territory to itself. 240 and 301 cover the same ground, serving Baltimore and the rest of the 227 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 227, ranked by how many ZIP codes each holds.
CityZIP codesCounty or independent city
Baltimore42Anne Arundel County
Silver Spring16Montgomery County
Bethesda11Montgomery County
Gaithersburg9Montgomery County
Annapolis8Anne Arundel County
Rockville8Montgomery County
Bowie7Prince George's County
Hyattsville7Prince George's County
Laurel7Anne Arundel County
Frederick6Frederick County
Hagerstown6Washington County
Capitol Heights5Prince George's County
Cumberland5Allegany County
Upper Marlboro5Prince George's County
Waldorf4Charles County
College Park3Prince George's County
Columbia3Howard County
Ellicott City3Howard County
Germantown3Montgomery County
Greenbelt3Prince George's County

197 further communities not listed. All Maryland area codes →

Each point is a community served by 227, 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 227. 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 and independent cities

Prefixes inside 227

We do not publish the NXX prefixes inside 227. 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

227 is the newer code here, added in 2023 over 240 (1997) and 301 (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 227 since.