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US area code · Maryland

Area code 240

Where the 240 area code is, its overlay and how to dial a +1 240 number from anywhere.

CoversAspen Hill, MarylandTime zoneEastern (ET)TypeOverlay
Quick answer

The 240 area code is in Aspen Hill, Maryland, United States (Eastern (ET)). To call from abroad: +1 240 555-0123. It is an overlay, so all 10 digits are dialled.

StateMaryland
Main areaAspen Hill
Time zoneEastern (ET)
TypeOverlay
10-digit dialingRequired
In service since21-Jun-1996

The 240 area code is a geographic North American Numbering Plan (NANP) code covering Aspen Hill, Maryland. It has been in service since 21-Jun-1996 and sits in the Eastern (ET) time zone.

Overlay 240 shares its region

Several area codes cover the same geographic area, so two neighbours can have different codes. Because of the overlay, you must dial all 10 digits (area code + number) even for local calls.

240227301

How to dial a 240 number

From abroad+1 240 555-0123
Within the US / Canada1 240 555-0123
Locally (same area)240 555-0123

Cities in the 240 area code

A 240 number is usually in one of these places in Maryland — 6 counties.

Aspen HillBowie Prince GeorgesChillumClinton Prince GeorgesCollege Park Prince GeorgesCumberland AlleganyFairlandFort Washington Prince GeorgesFrederick FrederickGaithersburg MontgomeryGermantown MontgomeryGreenbelt Prince GeorgesHagerstown WashingtonLandoverMontgomery Village MontgomeryNorth BethesdaNorth PotomacOlney MontgomeryPotomac MontgomeryRockville MontgomerySaint CharlesSilver Spring MontgomerySouth LaurelSuitland Prince GeorgesWaldorf CharlesWhite Oak

Other Maryland area codes

227301410443667

Frequently asked questions

Where is the 240 area code?

The 240 area code is in Aspen Hill, Maryland, United States (Eastern (ET)).

Is 240 an overlay area code?

Yes. 240 overlays the same region as 227, 301, so callers dial all 10 digits.

Do I have to dial 10 digits for 240?

Yes — dial the area code plus the seven-digit number.

How do I call a 240 number from another country?

Dial your exit code (or +), then 1, then 240, then the number: +1 240 555-0123.

Source: NANPA numbering plan. An area code covers a region, not a precise address — a 240 number does not pinpoint a street or ZIP code.

Missed a call from +1 240?

In the 30 days to September 24, 2026, 590 unwanted calls showing a 240 number were reported to the US Federal Trade Commission, 59% of them recorded messages or robocalls. That puts 240 at #142 of 670 area codes reported.

Other217
Reducing your debt (credit cards, mortgage, student loans)112
Calls pretending to be government, businesses, or family and friends94
Dropped call or no message67
Before you call back
  • If you do not know anyone in Maryland, do not call back: a genuine caller will leave a message or send a text.
  • Scammers fake the number shown on caller ID, so a 240 number can hide a caller anywhere in the world.
  • Never give a code received by text or a bank detail to an unknown caller. In the US, calls can be reported at reportfraud.ftc.gov.

Who issues +1 240 numbers

Phone companies hold blocks of numbers in each area code. The main holders in 240:

Omnipoint Communications Cap Operations, LLC 117Cellco Partnership Dba Verizon Wireless 85New Cingular Wireless PCS, LLC 69Paetec Itel, LLC 63Level 3 Communications, LLC 59Onvoy, LLC 56

About 19.4% of the 800 prefixes in use belong to mobile carriers: a 240 number is often a cell phone, and it may have moved to another carrier since.

Sources: FTC Do Not Call reported calls (numbers as reported by consumers, not verified), NANPA central office code assignments.

All US area codes United States +1 Map of area code 240 — cities & rate centres