The 240 area code is a Maryland area code. It covers the Maryland suburbs of Washington, D.C., southern Maryland and the western part of the state. It shares the area with 301 and 227.
This guide lists the cities in 240 and explains the time zone, the history and how to deal with unknown 240 calls.
240 Area Code Quick Facts
| State | Maryland |
| Location | Western Maryland and the Maryland suburbs of Washington, D.C. |
| Time zone | Eastern Time (UTC-5, UTC-4 during daylight saving time) |
| In service since | June 1, 1997 |
| Type | Overlay area code on 301 |
| Shares its area with | 301 and 227 |
| Toll-free? | No, it is a regular geographic area code |
Check any other code with our free area code lookup tool.
Where Is the 240 Area Code Located?
Area code 240 is located in the western half of Maryland. Main cities and communities:
- Silver Spring
- Rockville
- Bethesda
- Gaithersburg
- Germantown
- Frederick
- Hagerstown
- Waldorf
- Cumberland
It serves Montgomery, Prince George’s, Charles, St. Mary’s, Washington, Allegany and Garrett counties and most of Frederick County. Baltimore is not in 240. It uses 410, 443 and 667.
What Time Zone Is the 240 Area Code In?
This part of Maryland is on Eastern Time.
- Eastern Standard Time (EST), UTC-5, in winter
- Eastern Daylight Time (EDT), UTC-4, from mid March to early November
That makes it three hours ahead of Los Angeles and one hour ahead of Chicago. If you are calling for business, 9 a.m. to 5 p.m. local time is the safe window.
History of the 240 Area Code
- 1947: 301 is created for the entire state of Maryland.
- 1991: Baltimore and the Eastern Shore are split off as 410.
- June 1, 1997: 240 is added as an overlay on 301.
- June 14, 2023: 227 starts service as a second overlay.
Next Door to Washington
Montgomery and Prince George’s counties wrap around the north and east of Washington, D.C. Many federal agencies, research institutes, hospitals and contractors are located on the Maryland side, so official and work-related calls from 240 and 301 are routine across the capital region. See our 202 area code guide for Washington itself.
How to Dial a 240 Number
Because more than one area code can serve the same streets, always dial the full ten-digit number.
- From the US or Canada: 1 + 240 + the seven-digit number
- From another country: your exit code + 1 + 240 + the seven-digit number
Is a Call From 240 a Scam?
A 240 number is usually a resident or employer in the Maryland suburbs. Because so many federal offices are nearby, scam callers sometimes use 240 or 301 numbers when they pose as a government agency.
Watch for these warning signs:
- A recorded voice that says an account is locked or suspended
- A caller who wants payment by gift card, wire transfer or crypto
- A text with a link about a delivery, a toll or a refund
- A request for a one-time code that was just sent to your phone
Caller ID can be spoofed, so the number on your screen does not prove where a call comes from.
What to do with an unknown 240 call
- Let unknown numbers go to voicemail. A real caller leaves a message.
- Look up the company and call the number on its website.
- Block the number on your phone.
- Report scam calls at reportfraud.ftc.gov and register at donotcall.gov.
- Forward spam texts to 7726 (SPAM).
How to Get a 240 Phone Number
A local 240 number helps a business look established in the Washington suburbs.
- Carriers: new lines in the area are assigned 240, 227 or 301 depending on which has free numbers.
- VoIP and virtual number providers: search by area code, pick a 240 number and forward calls to any phone.
- Toll-free numbers: a better fit if your customers are spread across the country.
Read our guides to virtual phone numbers and the 800 area code.
Area Codes Near 240
| 301, 227 | Same area as 240 |
| 410, 443, 667 | Baltimore and the Eastern Shore |
| 202, 771 | Washington, D.C. |
| 703, 571 | Northern Virginia |
| 304, 681 | West Virginia |
Related guides: 202 area code for Washington, D.C., 302 area code for Delaware, 717 area code for south-central Pennsylvania.
240 Area Code FAQs
Where is area code 240?
In Maryland. It covers the Washington suburbs such as Silver Spring, Rockville and Bethesda, plus Frederick, Hagerstown and western Maryland.
What is the difference between 240 and 301?
They cover the same area. 301 dates from 1947 and 240 was added in 1997.
Is Baltimore in 240?
No. Baltimore uses 410, 443 and 667.
What time zone is 240?
Eastern Time.
Is 240 a toll-free number?
No. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.
Final Word
The 240 area code covers the Washington suburbs and western Maryland on Eastern Time. It has been in service since 1997, next to 301 and 227. Let unknown callers leave a message first.
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