Area codes · United States

Area codes in Maryland

6 in service
2 overlay complexes

Reviewed by Sujan ThapaliyaLast updated August 23, 2026

What area codes does Maryland use?

Maryland has six area codes: 227, 240, 301, 410, 443, 667. All of them are in ET (UTC−5/−4).

Codes in service: 6
Country: United States
Time zones: ET (UTC−5/−4)
Overlay complexes: 227/240/301, 410/443/667; Same territory, more than one code.
Oldest / newest code: 1947 / 2023

How many area codes does Maryland have?

Each page covers where the code is, its time zone, the overlays sharing its territory, and what to do about unwanted calls from it.

6 in-service geographic codes, from the numbering plan administrator's register.
Code	Time zone	Overlays	In service
227	ET (UTC−5/−4)	240, 301	2023
240	ET (UTC−5/−4)	227, 301	1997
301	ET (UTC−5/−4)	240, 227	1947
410	ET (UTC−5/−4)	443, 667	1991
443	ET (UTC−5/−4)	410, 667	1997
667	ET (UTC−5/−4)	410, 443	2012

Overlays

Which codes share the same ground?

An overlay adds a second code across the same geography rather than splitting the region in two, so nobody has to change their number — but every local call then needs ten digits, because seven no longer identifies a number uniquely.

227 / 240 / 301 — 3 codes over one territory.
410 / 443 / 667 — 3 codes over one territory.

Unwanted calls

Is a call from a Maryland code likely to be spam?

Not because of the code itself. Every code here serves real people and businesses. What makes an unfamiliar Marylandnumber suspicious is a pattern rather than a prefix: unwanted callers routinely spoof caller ID to display a number in the recipient’s own area, because a familiar code is answered more often. That technique is called neighbour spoofing, and it means the code on your screen is evidence of what the caller wanted you to see rather than where they are.

The practical response is the same for every code: if you do not recognise the number, let it go to voicemail. A caller with a genuine reason leaves a message. If the calls repeat, report them — complaints are one of the strongest inputs into the analytics that get numbers labelled and blocked network-wide, which does more than blocking one number on one handset. There is a fuller treatment in how to block unwanted calls.

If it is your own calls into Maryland going unanswered, the cause is usually the reverse of this: a number with no name attached to it, or one whose reputation was damaged before you rented it. Owning the number and registering a business name against it is what separates a local call that gets answered from one that gets ignored.

Frequently asked questions

How many area codes does Maryland have?

Maryland has six: 227, 240, 301, 410, 443, 667. That count changes as new overlays go into service, which happens when an existing code runs low on numbers.

What is the main area code for Maryland?

There is no single main code. Maryland is covered by six codes, and where two or more overlay the same territory neither is more "correct" than the other — a business on one street can hold numbers in either.

Why do some Maryland numbers need ten digits for a local call?

Because overlays cover the same ground as the original code — 227, 240 and 301; 410, 443 and 667. Once two codes serve the same street, seven digits no longer identify a number uniquely, so every local call needs the area code too.

Does an area code tell me where the caller is?

Where the number was issued, not where the person is now. Mobile numbers keep their code when their owner moves, and businesses port numbers between locations, so treat a Maryland code as a hint about origin rather than a location.

Can I get a Maryland phone number for my business?

Yes. Local numbers in any in-service code can be provisioned and are yours to keep, port and route. Presenting a number local to the person you are calling measurably lifts answer rates, provided it is a number you own and answer.

Sources

North American Numbering Plan Administrator — NANPAArea code assignments, relief planning, and which codes are in service across the North American Numbering Plan.
ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

Get a Maryland number that gets answered

A local code helps only when the number is genuinely yours and rings back to your team. Owned numbers, your business name on the caller ID, and calls signed at full attestation.

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