443 Area Code: Baltimore and Eastern Maryland Location and Time Zone

Introduction

The 443 area code is a Maryland code for Baltimore, the counties around it and the Eastern Shore, from Towson and Annapolis to Salisbury. It has no map of its own: 443 was laid over the existing 410 territory in 1997, and a third code, 667, joined both of them in 2012.

That layering explains most of what people ask about 443 numbers: why every local call includes the area code, why next-door neighbors can have different codes, and why a new line might come with 410, 443 or 667. Below are the counties and towns it covers, its time zone, how to dial it and how to judge a call you weren't expecting.

Where Is the 443 Area Code?

Area code 443 covers the eastern half of Maryland. Its boundary is the one drawn for 410, which the North American Numbering Plan Administrator (NANPA) records as entering service on October 6, 1991, when the Baltimore region and the Eastern Shore were split away from 301. Rather than redraw that line again, Maryland added new codes on top of it, so 443 and 667 cover exactly the same ground as 410.

In practice, a 443 number was issued somewhere in the Baltimore metropolitan area, in Calvert County on the western shore of the Chesapeake Bay, or on the Eastern Shore. Most of western and southern Maryland, including the Washington, D.C. suburbs, sits outside it and uses other codes.

Searches such as "area code 443 usa" or "what state is area code 443" all lead to the same answer: 443 is a US area code used only in Maryland. A 443 caller is not necessarily in Maryland today, though, because a mobile number can stay with its owner after a move.

Cities and Counties in the 443 Area Code

The counties below are the ones AT&T lists for 443, and they match the county list in Maryland's numbering history. Some are only partly inside the area, so treat the table as a guide to where 443 numbers come from rather than a boundary map.

Since all three codes serve every place on that list, the digits at the front of a number can't tell you which county it came from. A 667 line in Ocean City is just as local as a decades-old 410 line in Towson or a 443 cell phone in Glen Burnie.

Maryland's other codes serve the rest of the state. The Maryland area codes page puts them side by side.

443 Area Code Time Zone (Eastern Time)

Every 443 number is on Eastern Time. Maryland lies entirely in the Eastern zone, and NANPA's area code records list 410, 443 and 667 as Eastern.

Baltimore follows the national daylight saving schedule, moving clocks forward at 2:00 a.m. on the second Sunday of March and back at 2:00 a.m. on the first Sunday of November. That means Eastern Standard Time (UTC-5) through the winter and Eastern Daylight Time (UTC-4) in summer, which keeps the area three hours ahead of the Pacific coast all year.

443, 410 and 667: One Area, Three Area Codes

An overlay adds a code to a territory without moving anyone to a new one. Eastern Maryland has used that approach twice since the 1991 split, so the region's history reads as one boundary change followed by two layers of new numbers.

• October 6, 1991: 410 entered service, splitting the Baltimore region and the Eastern Shore away from 301.
• 1997: 443 was added on top of 410, covering the same territory.
• March 24, 2012: new lines and added services could start receiving 667 numbers. No existing 410 or 443 number changed.

The Maryland Public Service Commission's FAQ on the 667 change made one point clearly: 410 and 443 customers already dialed ten digits, so the third code didn't change how they placed calls. Their numbers, the price of a call, their coverage area and what counted as a local call all stayed the same.

Which of the three codes a new line receives depends on the numbers a carrier has on hand. Beyond that, the codes are interchangeable, and none of them marks a caller as more or less local than the others.

443 Area Code vs ZIP Codes

There is no "443 zip code." Area codes divide the telephone network under the North American Numbering Plan, while ZIP codes sort mail for the U.S. Postal Service, and neither system follows the other's boundaries.

The 443 area runs from dense Baltimore neighborhoods to small Eastern Shore towns, so it spans a long list of ZIP codes. To find the one for a particular Towson office or Salisbury street, use the ZIP Code lookup on usps.com with the full address.

How to Tell If a Call From 443 Is Legitimate

Most calls from 443 numbers come from ordinary Maryland households and businesses. Still, the area code proves nothing about the caller: the FTC warns that scammers can make any name or number appear on caller ID, including numbers that share your own area code so the call looks local.

If a call matches any of these, hang up and contact the organization through a number you already trust, such as the one printed on your card or a recent bill. If you lost money or shared personal information, report it at ReportFraud.ftc.gov; if you only want to report the unwanted call, use DoNotCall.gov.

To cut down on repeat calls, block the number in your phone's settings, ask your carrier which call-blocking or call-labeling services it offers (some are free, others cost extra), or install a call-blocking app. On a landline, a plug-in call-blocking device does the same job. Carriers also verify caller ID behind the scenes, as our explainer on STIR/SHAKEN caller ID authentication describes.

How to Dial a 443 Phone Number

Inside eastern Maryland the rule is simple: always include the area code. Verizon's notice for the 667 launch described it as the area code plus the seven-digit number for local calls, and 1 plus the area code and number for long-distance calls.

Three-digit services still take three digits where they're offered, including 211, 311, 411, 511, 611, 711, 811 and 911. And a local call stays local no matter how many digits you dial.

How to Get a 443 Phone Number for Your Business

A Baltimore-area number lets Maryland customers see a familiar code when you call, and a cloud phone system means that number can ring wherever your team actually works, with no desk in Baltimore required.

Because 410, 443 and 667 share one territory, search all three. Any of them is local to the same callers.

1. 1Pick the code. Browse the Maryland area codes Ringflow offers and check whether 443, 410 or 667 numbers are available.
2. 2Route the calls. Send calls to the Ringflow mobile and desktop apps, or put an auto attendant in front so callers can choose a team.
3. 3Add texting. Turn on business texting so customers can message the same number they call.
4. 4Or bring your number. If you already have a 443 line, port it and keep the number your customers know.

Ringflow includes local numbers in US area codes, call forwarding to its mobile and desktop apps, an auto attendant, business texting and number porting, and a free trial lets you test the whole setup first.

Conclusion

The 443 area code is eastern Maryland's second code, added in 1997 on top of the 410 map that covers Baltimore, its suburbs, Calvert County and the Eastern Shore. Since March 24, 2012, 667 has shared that map as well, and every local call there includes the area code.

If a 443 number calls out of the blue, judge what the caller asks for rather than the digits on the screen, and report scams to the FTC. If a Maryland number would help your own business, browse US area codes and start a free Ringflow trial.

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