Phoenix, Arizona is one of the fastest growing cities in the nation and is currently the fifth largest city. Phoenix has endless summers, a good economy and covers a large area so does not look so crowded like other large cities. The current population of the Phoenix area is over 3.3 million people and due to the growth there was a need for a new area code. The area code 602 was used for the entire Phoenix area and eventually ran out of telephone numbers. This was due to the growth and also the new technology where there is an increased demand for numbers for fax machines, pagers, cellular phones, second telephone lines and other services.

An area code is a three-digit prefix used to indicate the destination area for long distance calls and occasionally local calls. It is also known as Numbering Plan Area (NPA). The telephone numbers are grouped geographically for anyone to reach a certain area who is outside the area and allows them to connect directly with the desired number.

On September 1, 1999 two new area codes went into effect in the Phoenix, AZ area. 480 and 623 area codes in the valley area were now required to make a call. The Numbering Plan Administrator, the body that maintains the integrity of all area code numbers stated the new area code being 623. The central Phoenix area used (602) area code and the east valley uses (480) area code. The NorthWest valley now has the area code of 623. To place a local call from the 602 area code to a number in the 623 area code, you would need to dial 623-XXX-XXXX. There is no need to dial a "1" before the ten-digit local number. You only need to dial a 1 if you are dialing a non local call. These calls that are local are free and not long distance.

Cities in the 623 Area Code