240 Area Code — Maryland

240 is a North American Numbering Plan area code for Maryland, the United States. It covers about 2,823,102 people in 164 towns and 265 ZIP codes, including Silver Spring, Hyattsville and Frederick.

Where area code 240 is used

Area code 240 is assigned to Maryland, the United States, inside the North American Numbering Plan. Numbers in the code are written (240) NXX-XXXX at home and +1 240 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.

Other area codes in this footprint: 301, 227. They serve towns in the same territory, so a single street can contain numbers from more than one code. That is normal in the NANP and does not change how you dial.

Towns and cities in area code 240

The 164 towns below are the largest in the 240 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.

Counties covered

Other area codes serving the same towns

Nearby area codes

How to dial area code 240

• Within North America: 240 + 7-digit number (240-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
• From abroad: your country's international prefix, then 1, then 240, then the 7-digit number — for example 00 1 240 NXX-XXXX from most of Europe.