240 Area Code — Frederick, MD
Area code 240 serves Frederick and 3 other cities in Maryland. Local time follows America/New_York. It overlays with 301, 227, so 10-digit dialling is required.
- State
- Maryland
- Primary city
- Frederick
- Timezone
- America/New_York
- In service since
- 1997
- Type
- Overlay
Overlay of 301
Cities Served by 240
The 240 area code covers 4 cities and communities in Maryland.
- Frederick
- Hagerstown
- Rockville
- Silver Spring
About Area Code 240
Area code 240 is a North American Numbering Plan (NANP) area code that has been in service since 1997. It is administered by NANPA on behalf of the FCC and serves the Maryland region anchored on Frederick.
240 is an overlay code, which means it shares its geographic boundaries with one or more existing area codes (301, 227). Overlays are created when a region exhausts the supply of phone numbers in its original area code. Within an overlay region, residents must dial all 10 digits even for local calls, because the same 7-digit number can exist under multiple area codes.
Mobile numbers in 240 are portable: a person who moved away from Frederick may still carry a 240 mobile number on their device. If you receive an unexpected call from a 240 number, run it through the reverse lookup tool above for the most accurate, free identification.
If you live or do business in Maryland, you may also interact with neighbouring or overlay codes (301, 227). See the related codes section below to explore the rest of Maryland.
Other Maryland Area Codes
Continue exploring the Maryland numbering plan.
240 Area Code FAQ
Where is area code 240?
Area code 240 is located in Maryland, primarily serving Frederick and surrounding cities including Hagerstown, Rockville, Silver Spring. The region operates on ET (America/New_York) time.
What state is 240 area code?
240 is a Maryland area code. It was put into service in 1997 as an overlay and shares its geographic footprint with overlay codes 301, 227.
Is 240 a scam area code?
240 is a legitimate North American area code allocated by NANPA to Maryland. Like any geographic area code, scammers sometimes spoof 240 numbers — judge each call by content (urgent demands, unfamiliar transfers) rather than the area code alone. Run the specific number through our reverse lookup if you're unsure.
What time zone does 240 use?
Area code 240 operates on ET (America/New_York). Numbers in this area code follow standard Maryland time-zone rules including any daylight-saving transitions for that region.
Can I look up a specific 240 phone number?
Yes. Use the reverse lookup widget above to enter a full 240 number. NumLocation returns the line type (mobile, landline, VoIP), carrier, rate-center city, and any public listings tied to the number — free.
What's the difference between 240 and 301?
240 and 301 cover the same Maryland geographic area as overlay codes. Calls between them are local, but you must dial all 10 digits. New phone numbers in this region are assigned from either pool depending on what's available with the carrier at signup.