Format of Washington, DC Phone Numbers

In Washington, DC, Northern Virginia, Maryland, and throughout the United States, landline and mobile phones have identical 10-digit numbering formats.

There is no way to tell by looking at a written telephone number whether it is a landline number or a cell phone number. This contrasts with some countries where mobile numbers and landline numbers can be different.

When written, a Washington, DC telephone number will almost always include all 10-digits required for dialing. This is because even when dialing within the United States, even to a number just down the street, the entire 10-digit phone number must be dialed.

In some cases, you may find a Washington, DC phone number written with 11-digits. In such case, the 11th digit will be a leading ' 1 ' which is used for both domestic long distance dialing and for inbound international dialing. The United States is one of the few countries with the same country code and national direct dial (NDD) code.

The format of Washington, DC phone numbers and all numbers throughout the United States are governed by the North American Numbering Plan (NANP). A total of 18 other countries participate in the plan, in addition to the USA.

For further information:

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Washington, DC Landline Phone Numbers

Washington, DC landline phone numbers are always 10-digits long and include two parts: an area code and a local subscriber number.

Washington, DC Landline Phone Number Format

 aaa   nnn nnnn 
area
code		 local subscriber
number

Generally, a Washington, DC landline phone number will be written with dashes and look like this: aaa-nnn-nnnn as in 202-509-6995. Phone numbers are also written equivalently as: (202) 509-6995.

In some cases, the 10-digit number will be preceded by a ' 1 ' signifying both the country code and domestic long distance code. For instance, 1-202-509-6995 or 1 (202) 509-6995.

Washington, DC Landline Area Codes

Washington, DC landline area codes are always 3-digits long and are almost always included in written phone numbers. Landline area codes are indistinguishable from mobile area codes.

In written phone numbers, it is not uncommon to see the area code preceded by a ' 1 ', as described above.

Like any large metropolitan area in the United States, Washington, DC uses multiple area codes. Originally, any given area had a single unique area code, but as more and more numbers have been added, Washington, DC has gone to an overlay system where new area codes are added within the same geographic footprint.

You can find a complete list of Washington, DC area codes here.

Washington, DC Local Subscriber Numbers for Landlines

Landline subscriber numbers in Washington, DC are always 7-digits long. Mobile numbers are likewise 7-digits.

Landline Subscriber Codes for Major US Carriers

Whereas in some countries it is fairly easy to determine what company issues what phone number, in the United States this is not so easy - and, for the most part, not so necessary because detailed phone number information is usually readily available.

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Washington, DC Mobile Phone Numbers

Like landline numbers, Washington, DC mobile phone numbers are always 10-digits long and include two parts: an area code and a local subscriber number.

Washington, DC Mobile Phone Number Format

 aaa   nnn nnnn 
area
code		 local subscriber
number

Mobile numbers are written identically to landline numbers in this 10-digit format: aaa-nnn-nnnn. Examples: 202-509-6995 or (202) 509-6995.

As with landline numbers, mobile numbers may be preceded by a ' 1 ' which is used as both the country code and domestic long distance code.

Washington, DC Mobile Area Codes

Area codes for mobile numbers are the same area codes for landline numbers. They are always 3-digits long and are almost always included in written phone numbers.

Find Washington, DC area codes here.

Local Subscriber Numbers for Washington, DC Mobiles

Just like landline numbers, moible subscriber numbers in Washington, DC are always 7-digits long.

Mobile Subscriber Codes for Major US Carriers

It is not readily possible to identify which US mobile carrier has issued what phone number. And, because there is as yet no public mobile phone number directories published in the US, it can be as hard to track down a person's mobile number in the US as it is in many other countries.

That said, there are a number of paid services that offer reverse number lookup and/or cell phone number lookup to find Washington, DC mobile customers.

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North American Numbering Plan

Phone numbers in Washington, DC and throughout the United States are governed by the North American Numbering Plan (NANP). In addition to the US, 18 other countries participate in the NANP numbering plan.

The plan was originally conceived by AT&T in 1947 as a way to simplify long distance dialing. Implementation of the plan began in 1951.

Over time, additional countries have joined the numbering plan, including Canada, the Bahamas, and Jamaica.

All countries participating in the plan use the same 10-digit numbering format of:

aaa nnn nnnn

This includes a 3-digit area code and a 7-digit local subscriber number.

For more information, please visit the North American Numbering Plan website.

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