The Old Line State

Maryland Calling
Codes 410 & 301

Calling Baltimore, Annapolis, or the DC suburbs? Maryland uses multiple area codes including 410, 301, 240, and 443. Connect instantly to any Maryland number from your browser.

How to Dial
Calling Maryland (US)Online
🇺🇸

How to Call Maryland Step-by-Step

Maryland has multiple overlay codes, so knowing the correct area code is crucial.

1

Exit Code

Dial your country's exit code (e.g., 00 for Europe, 011 for Asia). Skip if in US/Canada.

2

Country Code (+1)

Dial +1 for the United States.

3

Area Code

Dial the 3-digit area code (410, 301, 240, etc.) followed by the 7-digit number.

10-Digit Dialing is Mandatory

Because Maryland has multiple area codes covering the same geographic regions (overlays), you must always dial the full 10 digits (Area Code + Number), even for local calls.

Maryland City Codes

Common area codes for major Maryland cities.

CityRegionArea Code
BaltimoreCentral410 / 443
AnnapolisAnne Arundel410 / 443
Silver SpringMontgomery301 / 240
RockvilleMontgomery301 / 240
FrederickWestern MD301 / 240
CityRegionArea Code
Ocean CityEastern Shore410 / 443
GaithersburgMontgomery301 / 240
BowiePrince George's301 / 240
HagerstownWashington301 / 240
ColumbiaHoward410 / 443

Connect to Maryland Business
Instantly

From the biotech corridors of Montgomery County to the bustling port of Baltimore, Maryland is a hub of industry. StartACall gives you a professional connection to the state without the high cost of traditional carriers.

  • Reach 410, 301, 240, 443, and 667 numbers
  • Crystal clear HD voice quality
  • No app download required - use your browser
  • Pay-as-you-go pricing model

Save Money

Fraction of the cost of carrier roaming rates.

Any Device

Call from your laptop, tablet, or phone.

Secure

Enterprise-grade encryption for all calls.

Reliable

99.9% uptime for critical communications.

Frequently Asked Questions

What is the difference between 301 and 240?

They are overlay codes covering the same region (Western Maryland, including DC suburbs). 301 is the original code, and 240 was added later. Both work for the same cities.

What is the difference between 410 and 443?

Similar to 301/240, 410 and 443 (and the newer 667) are overlay codes for Eastern Maryland, including Baltimore and Annapolis.

How do I call a Maryland number from the UK?

Dial 00 (UK exit code) + 1 (US country code) + Area Code (e.g., 410) + 7-digit number.

Can I call Maryland cell phones?

Yes, you can call any mobile or landline number in Maryland. US mobile numbers look exactly like landline numbers and use the same area codes.

Ready to call Maryland?

Start making calls in seconds. No credit card required to sign up.

Maryland phone codes from overseas: two regions, five codes, ten digits always

In short

Maryland abandoned the idea of one code per city long ago. The Baltimore side of the state stacks 410, 443 and 667 on the same territory, while the Washington suburbs and the west share 301 and 240. Every call inside the state needs ten digits, and every call from outside needs +1 first.

Baltimore's stack and Washington's pair

The eastern half of Maryland, including Baltimore, Annapolis and the Eastern Shore, is served by 410 and its overlays 443 and 667. All three are interchangeable geographically, so a Baltimore plumber on 443 and a neighbor on 410 are equally local.

The 301 code covers the Washington suburbs, Montgomery and Prince George's counties, plus western Maryland out to Cumberland, with 240 overlaying the whole territory since 1997. Maryland was among the first states to adopt overlays, which is why ten-digit dialing has been standard here for decades.

The overlays arrived in waves as the two metros grew, 240 and 443 in the late 1990s and 667 in 2012. Each new code layered onto the existing region rather than redrawing boundaries, which kept everyone's numbers unchanged but ended seven-digit dialing for good across the state. Businesses that survived all the waves often hold numbers in more than one code.

Federal Maryland: who you are really calling

Many international calls to 301 numbers reach federal institutions rather than households. The National Institutes of Health in Bethesda, the FDA in Silver Spring and NIST in Gaithersburg all answer on 301 lines, and their switchboards keep strict 9am to 5pm Eastern weekday hours.

On the 410 side, Social Security's headquarters near Baltimore and Fort Meade's surrounding contractors generate heavy call volume. If you are calling an agency about a case, phone in the Maryland morning, since queues lengthen after lunch and close abruptly at day's end.

Annapolis adds state government to the mix, with the legislature and agencies answering on 410 numbers, plus the Naval Academy, whose switchboard fields international calls year round. Chesapeake Bay tourism numbers on the Eastern Shore are seasonal, busiest from spring through the autumn sailing season and quiet in deep winter. The legislative session runs January to April, the busiest phone months in Annapolis.

Dialing rules and Eastern Time planning

From abroad, dial +1 and the ten digits shown, whichever of the five codes begins the number. Maryland mobiles use the same codes as landlines and, via StartACall, cost the same per minute from your browser, pay-as-you-go with no connection fee, and the first call is free.

Maryland shares Washington DC's clock, Eastern Time, five hours behind UTC in winter. From Europe, 3pm to 10pm local European time covers the business day and early evening. From West Africa, Maryland's morning starts around 2pm to 3pm local, a comfortable afternoon window for family calls.

Baltimore's port and the BWI airport corridor run around the clock, so logistics lines answer at any hour even when offices are closed. For everything else, Maryland follows standard East Coast rhythms, with the heaviest phone traffic between 10am and noon Eastern, worth avoiding if you want short hold times. Weekend answering is rare outside hospitals and the port.

Frequently asked questions

What area code is Baltimore Maryland?+

Baltimore uses 410, 443 and 667, three overlaid codes covering the same territory including Annapolis and the Eastern Shore. Any of them can appear on a Baltimore number. Whichever appears, dial +1 and the full ten digits from overseas.

What is the 301 area code?+

301, together with its overlay 240, covers western Maryland and the Washington DC suburbs, including Bethesda, Silver Spring, Rockville and Frederick. Both codes reach exactly the same territory at identical per-minute cost.

Is 443 a mobile area code?+

No code in the US is mobile-only. 443 is simply a newer overlay for the Baltimore region, assigned to both mobiles and landlines, and costs the same to call. US codes are shared by mobiles and landlines alike.

Do I need to dial all ten digits for Maryland?+

Yes. Maryland has used overlays since the 1990s, so ten-digit dialing is universal. From abroad, add +1 in front of the full ten-digit number. Numbers there are always printed in full ten-digit form.

What time should I call Maryland from Europe?+

Maryland is on Eastern Time, five hours behind the UK in winter. Calling between 2pm and 10pm UK time reaches Maryland during its working day and evening. Daylight saving narrows the gap to four hours each summer.

Last reviewed June 2026Reviewed by the StartACall calling teamDialing rules cross checked against ITU international dialing procedures
Nearby dialing codes

Other country and area codes

Related country codes, area codes, and regional dialing guides for your next call.

Alabama area codes
Alaska area codes
Arizona area codes
Arkansas area codes
Bermuda country code
California area codes
Canada country code
Canada Business country code
Colorado area codes
Connecticut area codes
Delaware area codes
District Of Columbia area codes
See all international calling routes