Phone Number Area Codes in the United States

When calling anyone in the US, whether your friend, business partner, customer, or family member, you need their phone number, which always comes with a three-digit area code. And as you may have guessed, the area codes differ depending on the location of the person you are trying to call or message.

This comprehensive article will explain everything you need to know about phone area codes, the reason for their creation, the format in the US, and so on. As a plus, we will list all the area codes in the US, so you won’t run into any issues when you want to call your friends and family.

Want to learn all that and more? Keep reading to learn more!

What Is a Phone Number Area Code?

In simple terms, a phone number area code is a part of a telephone number that represents the broad geographical area to which the phone number belongs. The section precedes the local number after the country and access codes. In the United States, an area code is a three-digit number you will see before the local number, which is seven digits long. Thus, if you call someone in the Western US, you can expect the area code listing to be different from a number in the Northeast US.

However, one thing to note is that you don’t need to dial the area code of a telephone number if you are in the same area as the person you are trying to call. But do not confuse this with the three prefix numbers in the local number, which often represent a more specific area, such as the neighborhood or town that the number belongs to. Area codes denote a wider region, either an entire county in a state or a more significant segment of a city.

The Main Reason for Area Codes Creation

The history of area codes can be traced back to the 1940s. The Bell Telephone Company and AT&T invented the concept after dividing the coverage area into “number plan areas,” which has revolutionized the industry. Before the invention, routing and switching phone calls were done manually, which required many human operators and additional expenses. For instance, if you want to call someone, you first have to place a request to the exchange center that the person belongs to and likely state their name and number. It is only after then that the operators connect you to the line.

The main reason for creating area codes is to eliminate the delay that comes with the previous routing and switching methods. Now, phone numbers are purely numerical, and with area codes, the switching and routing of phone calls are automated. The system checks the dialed number and can quickly determine the area the call is targeted through the area code. This makes for better and faster switching of phone calls, with almost no noticeable delay. So when you send a marketing message using platforms like Textback.ai, the message is delivered to the specific device with the phone number.

Telephone Number Format

To better understand how area codes work, it’s essential to look at the telephone number format. The organization and allocation of phone numbers in the US is governed by the North American Numbering Plan Administration (NANPA). The formatting convention used for phone numbers is (NPA) NXX-XXXX. But what exactly does that mean?

The NPA represents the area code of three digits, representing a broad area into which a phone number falls. It is usually based around major cities or counties. For instance, 405 is the area code of Oklahoma City, which means that you must add this code when calling a phone in this location from somewhere else.

The NXX-XXXX is referred to as the telephone number, but it is further divided. The prefix NXX is a three-digit code that represents the central office or exchange area that the phone number belongs to. The “N” in the three digits can start from 2 to 9, while the “X” can be any digit from 0 to 9. This code helps make it possible for the switching center to identify the smaller area or neighborhood to which a phone number belongs.

The last part of the telephone number format, “XXXX”, is called the line or subscriber number. This is specific to a subscriber or user within an exchange area. And based on the current total number of active NPA and NXX combinations, there are around 10,000 possible line numbers per exchange center.

How Many Area Codes Are There in the United States?

According to the NANP, there are hundreds of possible area code combinations, but many are not in use, while some codes are also reserved for special purposes. Nevertheless, the US currently has 317 geographical area codes and 18 non-geographical area codes, bringing the total to 335 US area codes. 

US Country Code

But you may wonder – what then is the “+1” that sometimes precedes a US phone number? This is the country code you must enter if you call from another country. You can think of it as a pointer that informs the international switching center (ISC) of the country a call is intended for. For example, assuming you are planning an SMS marketing campaign to send to your subscribers abroad, you need to include the country code for your message to be successfully delivered.

However, it’s worth noting that 25 countries, including the US, share the +1 prefix. This can be surprising, especially considering that other countries have unique country-calling codes. But how, then, does the ISC differentiate which call is meant for a US phone number? That is another aspect where the area codes come into play. With the North American Numbering Plan, it is possible to determine which area a call is intended for, so it can be processed appropriately.

Phone Number Area Codes of Western US

Also called the Far West, the Western US comprises 13 states. It is a region home to the Rocky Mountains and split into subregions – Mountain States and the Pacific States. Presently, this region is served by 68 area codes, and 35 of these codes belong to California. This is understandable since California has several areas, such as West Los Angeles, San Diego North County, San Fernando Valley, Coastal Orange County, San Francisco County, parts of Santa Clara County, and so on. As for Nevada, you will find areas like the Clark County area and some parts of Las Vegas. Utah also has areas like the Salt Lake City Metro.

Here is a full list of Western US area codes by state.

Phone Number Area Codes of Northeast US

Another region of the US we are considering for their area codes is the Northeast US. This region is made up of 9 states: Pennsylvania, New York, New Hampshire, Rhode Island, New Jersey, Maine, Connecticut, Vermont, and Massachusetts. Despite having just 9 states, the Northeast US uses 57 area codes, with New York having 19 of these codes.

In Connecticut, you will find New Haven, Fairfield County, and New Haven counties, while in New Jersey, areas like Jersey City and the St. Louis metro area. As for New York, the areas include Suffolk County, Delaware County, and Westchester County.

Below, we have provided a list of the area codes per state in this region.

Phone Number Area Codes of Midwest US

Also called the north-central United States, the Midwest United States consists of 12 states and 79 local area codes. Of these 79 area codes, 14 serve Illinois and 13 serve Ohio. Wisconsin has areas such as Louis and Kansas City, and Milwaukee County, while Michigan has upper central Michigan, Oakland County, Sturgis, and Lake Michigan. As for Missouri, you will find areas like the Kansas City area, the Jefferson County area, and St. Louis City. On the other hand, Ohio has areas like the Cleveland metro area.

Here is a full list of phone number area codes for the Midwest US:

Phone Number Area Codes of South US

Of all the regions in the US, the South has the highest number of states and area codes. The region comprises 16 states and 115 area codes, including popular ones like 281 in Houston and 512 in Austin. Of the 115 area codes, Texas has 27, the highest, while Florida has 18.

Florida has areas like Palm Beach County, while Alabama has the Mobile and coastal areas. In Georgia, you will find areas like the Greater Atlanta Metropolitan Area; Louisiana, the New Orleans metro area; and Tennessee, the Memphis metro area.

Below are the area codes of each state in the South US:

Non-Geographic Area Codes

As mentioned earlier, the US also has 18 non-geographical area codes. These are codes that are not assigned to any particular location and they include: 456, 500, 521, 522, 523, 524, 525, 526, 527, 533, 544, 566, 577, 588, 700, 710, 800, 833, 844, 855, 866, 877, 888, and 900. But what exactly are these codes used for?

No-geographical area codes are used for different services, such as voting on television shows, calling for information, making toll-free calls to businesses, making payments, and so on. Let’s take a quick look at some of these codes.

Toll-Free Area Codes

These area codes are 800, 888, 877, 866, 855, 844, or 833. Users dialing these codes are not charged for the call, which is why they are referred to as toll-free phone numbers. However, it is worth noting that these codes cannot be interchanged, according to the FCC.