Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — AREA-CODE/240

240 area code

Area code 240 is in Maryland. Local time there is , Eastern Time. In service since 1997 as an overlay: it covers the same area as 227 and 301, so a number from there can have any of them.

Time zone
Eastern
Overlays
227, 301
In service since
1997
Rate centres
63
Prefixes assigned
785 (7,850,000 numbers)

Who calls from a 240 number

NANPA records the carrier each block of 240 numbers is assigned to. Of the 7.7 million 240 numbers assigned, 54% are with cable, internet-calling, business and other carriers (Onvoy, Bandwidth and Core Communications); 41% with mobile carriers (T-Mobile, AT&T Mobility and Verizon Wireless); 5% with local phone companies.

That is who the numbers were assigned to: people keep their number when they change carrier, so any one number may have moved since.

Carriers holding the most 240 numbers
CarrierKindShare
T-MobileMobile21%
OnvoyCable, VoIP, other15%
AT&T MobilityMobile11%
Verizon WirelessMobile9%
BandwidthCable, VoIP, other7%
Core CommunicationsCable, VoIP, other6%

An area code says where a number was issued, not where the caller is: people keep their numbers when they move, and caller ID can be set to show any number, which the FCC calls spoofing. If a call you did not expect asks for money or personal details, the FCC advises hanging up and calling the company back on a number you look up yourself. Unwanted calls can be reported to the FTC at ReportFraud.ftc.gov.

Places in area code 240

The 39 places with a telephone rate centre of their own using 240, largest first. Each links to its ZIP codes.

Places in area code 240
PlaceZIP codesPopulation
Frederick, MD 6 83,395
Waldorf, MD 4 82,943
Gaithersburg, MD 9 69,825
Hagerstown, MD 6 43,665
Cumberland, MD 5 18,804
Brandywine, MD 1 12,160
La Plata, MD 1 10,683
Mount Airy, MD 1 9,805
Brunswick, MD 1 8,450
Frostburg, MD 1 6,977
Walkersville, MD 1 6,414
Thurmont, MD 1 6,254
Poolesville, MD 1 5,764
Middletown, MD 1 5,014
Leonardtown, MD 1 4,808
Indian Head, MD 1 4,055
Smithsburg, MD 1 3,115
Emmitsburg, MD 1 2,845
Myersville, MD 1 2,358
Oakland, MD 1 2,254
Nanjemoy, MD 1 2,129
Hughesville, MD 1 2,098
Williamsport, MD 1 1,949
Hancock, MD 1 1,625
New Market, MD 1 1,603
Westernport, MD 1 1,588
Flintstone, MD 1 1,404
Mechanicsville, MD 1 1,395
Buckeystown, MD 1 1,192
Keedysville, MD 1 1,183
Highfield-Cascade, MD — 1,089
Grantsville, MD 1 1,013
Lonaconing, MD 1 889
Mount Savage, MD 1 514
Friendsville, MD 1 416
McCoole, MD — 373
Clear Spring, MD 1 342
Kitzmiller, MD 1 264
Bittinger, MD 1 —

Nearby places using 240

These places have no rate centre of their own in NANPA's records; the nearest one uses 240. Near an area-code boundary that can be wrong for part of a town.

ZIP codes in area code 240

189 ZIP codes in 135 towns, by the town each is mailed to, largest first. Each links to its own page.

Where 240 numbers are issued

NANPA's rate centres with the most 240 prefixes (each prefix is 10,000 numbers), under NANPA's own abbreviated names.

Rate centres using area code 240
Rate centrePlacePrefixes
WSHNGTNZN3 — 73
WSHNGTNZN2 — 64
WSNGTNZN10 — 54
FREDERICK Frederick 43
GAITHERSBG Gaithersburg 40
LAUREL236 — 39

Counties

The counties of its ZIP codes, most residents first, with how many of its ZIP codes each has.

Which code covers where you are now? What area code am I in? answers from your location.

Questions about area code 240

Where is area code 240?

Area code 240 is in Maryland.

What ZIP codes are in area code 240?

189 ZIP codes, by the town each is mailed to: Germantown (3, 20874 to 20876), Frederick (6, 21701 to 21709), Waldorf (4, 20601 to 20604), Gaithersburg (9, 20877 to 20899) and 131 more towns. The full list is on this page.

What time zone is area code 240 in?

Eastern time.

Is a 240 number a mobile or a landline?

It can be either. 41% of 240 numbers are assigned to mobile carriers and 5% to local phone companies (NANPA, 2026-10-10); the rest are with cable, internet-calling, business and paging carriers. A number keeps its area code when it moves to another carrier.

What area codes overlay 240?

227 and 301. They cover the same area as 240, so a new number there can be given any of them.

Does a 240 number mean the caller is in Maryland?

Not necessarily. An area code says where the number was first issued. People keep their numbers when they move or switch carriers, and calling software can show any number, so a 240 call can come from anywhere.

Other area codes in Maryland

All 6 Maryland area codes, by area, with the cities each covers

Source: NANPA NPA database, central office code and thousands-block assignments, 2026-10-10. Places are matched to NANPA's rate centres by name; see sources.

Cite this page

zipcodes.pro. “Area code 240.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/area-code/240

Underlying data is public domain or openly licensed — sources, vintages and licences.