Area zip codes map

For instance, area code commonly referred to as numbers is reserved for toll free calls where the called party is charged instead of the calling party. Also, not all area codes are currently in use. The NXX is also known as the prefix or exchange. Various telephone carriers will reserve blocks of telephone numbers by reserving an NXX within an area code. Like area codes, not all prefixes are currently in use. Subscriber : Finally, the final 4 digits of the phone number are known as the subscriber or local number.

Based on the total number of active NPA and NXX combinations reserved and that each one could have up to 10, possible subscriber numbers, the current total possible number of telephone numbers is 1,,, Remember though that phone numbers are no longer just used for standard home phones. Many telephone numbers are now used for fax machines, cell phones or wireless phones, or internet connections so one person may actually need multiple phone lines.

They were created to prepare for a nationwide unified long-distance direct dialing system - the ability to make a call to any other calling area without the need for an operator.

The first digit did not allow a zero could be confused with the operator or a 1 techical reasons. At the time, rotary phones made it so that dialing lower numbers like 1 or 2 took less time to dial and dialing higher numbers took longer to dial. Area codes with lower numbers that were easier to dial were given to high population and high call volume areas. The original area codes only existed in the US and Canada.

Parts of Canada, Alaska, and Hawaii were not yet included. When the phone formats we commonly use today first came into service in the s and the s, blocks of phone numbers were allocated to a phone carrier in 10, phone numbers ie. Frequently, the 10, numbers would be enough for a small town with larger towns being allocated multiple prefixes.

Further, local phone carriers frequently had a monopoly on local phone service which prevented large portions of an allocated block from being unutilized.

In the s, cell phones became much more popular which created an explosion of demand for new phone numbers. Cell phones also reduced the monopoly of local phone providers which reduced utilization of allocated prefixes. Instead of a single primary phone carrier, cities had two or more carriers - each needing their own prefix. In addition, the rise in popularity in the internet dial up and DSL and voice over IP VOIP , local interenet service providers and cable companies started to request prefixes.

Many of these prefixes included few, if any, subscribers. For decades, new area codes were created through a "split" of an existing area code into multiple regions. Normally, the more populated region would continue to use the existing area code. The less populated areas would have all existing phone numbers reassigned to use a new area code to free up more numbers in the original area code. This process forced many into a new phone number which would require updates to letterhead, business cards, phone directories, personal contact lists, etc.

Many people would dial the incorrect area code which caused confusion. In , area code was created as the first "overlay" area code. With an overlay area code, the overlay serves the same geographic as the original to increase the pool of numbers available in the area. When the original phone systems were put in place, 7-digit dialing without the area code could be used to make local calls, and digit dialing with the area code only needed to be used for long distance calls.

In , area code was introduced as the first overlay with forced 10 digit dialing for local calls. Initially, there was substantial public resistance to overlays because of the digit dialing requirement for local calls. However, the last area code split in Canada was in with the split of splitting off and the last area code split in the US was in with splitting off No area code splits are currently proposed and both countries have agreed: without exceptional circumstances, all new area codes will be overlays.

Today, 7-digit dialing is broken in most major cities. Many areas not served by an overlay can still use 7-digit dialing. Something besides allocating more area codes needed to be done to improve the system. After a few trials, mandatory number pooling was implemented in with a national rollout to the largest metropolitan areas.

With number pooling, an entire prefix of 10, numbers is allocated to a specific area, but phone numbers are only allocated to a specific carrier in 1, block increments. While several US markets are still not required to implement number pooling and Canada has no number pooling, the effects dramatically slowed the need to allocate new prefixes and new area codes because of increased utilization.

The rate of issuing new area codes dropped to nearly half that of the s. While it may seem that all consumers in the US use a mobile phone, more than two-thirds of prefixes are allocated for landline use. That number has been dropping by about 3. The additional 4 digits help USPS more precisely group mail for delivery.

The map of the first digit of zip codes above shows they are assigned in order from the north east to the west coast.

The first 3 digits of a ZIP code determine the central mail processing facility, also called sectional center facility or "sec center", that is used to process and sort mail. All mail with the same first 3 digits is first delivered to the same sec center where it is sorted according to the last 2 digits and distributed to local post offices. The sec centers are not open to the public and usually do most sorting overnight. As you can see from the map of the first 3 digits of zip codes , the digits after the first are also generally assigned from east to west.

In the map, 0 is closer to white and 9 is much more vivid. It's easy to follow the gradient across each of the zones even though there are a few exceptions such as the southwest tip of Georgia which uses 39XXX like central Mississippi. Despite the fact that ZIP codes seem to be geographic in nature, that wasn't their intended purpose.

They are intended to group mail to allow the USPS to deliver mail more efficiently. Some ZIP codes will span multiple states in order to make mail routing and delivery more efficient. In most cases, addresses in close proximity to each other are grouped in the same ZIP code which gives the appearance that ZIP codes are defined by a clear geographic boundary.

However, some ZIP codes have nothing to do with geogaphic areas. When ZIP codes appear to be geographically grouped, a clear shape cannot always be drawn around the ZIP code because ZIP codes are only assigned to a point of delivery and not the spaces between delivery points. In areas without a regular postal route or no mail delivery, ZIP codes may not be defined or have unclear boundaries.

The main issue is discussed above: there simply isn't always a clear geographic boundary for a ZIP code. The Census Bureau and many other commercial services will try to interpolate the data to create polygons shapes using straight lines to represent the approximate area covered by a ZIP code, but none of these maps are official or entirely accurate.

They provide a very close approximation of the area covered by a ZIP code. You can easily notice some of the boundary issues when viewing our maps. Very rural areas aren't labeled as belonging to a ZIP code such as much of Nevada and Utah where there are few, if any, addresses to deliver mail. If the address is on the same street as a ZIP code boundary on the map, be sure to search for the full street address to determine the ZIP code instead of relying on the map.

Their purpose is to convey statistical data about regions that are familiar to most citizens. As discussed above, it is difficult to precisely define a geographic area covered by a ZIP code. ZCTAs were developed to account for some of the difficulties in assigning an area to a ZIP code and to precisely define a geographic area.

In general, they are updated once every 10 years for the Census. The Census assigns an area to a ZCTA according to census blocks the smallest geographic unit used by the census. Imagine a city block that makes up a typical census block as pictured to the right.