North American Numbers Source-cited · ownership disclosed
Area code
623
In service
United States · since 1999

West Valley (Glendale/Peoria/Surprise)

Created in 1999 as a West Valley split from 602, now part of the three-code overlay (480/602/623) covering the Phoenix metropolitan area.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
West Valley (Glendale/Peoria/Surprise)
Type
geographic
Status
in service
In service since
1999
Projected exhaust
2056 Q4

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 623 is

Western Maricopa County (Phoenix metropolitan area)..

Communities served wholly or partly by 623:

GlendalePeoriaSurpriseAvondaleGoodyearBuckeye

Since the 2023 overlay, 480/602/623 all serve the same Phoenix-metro geography; historically 623 covered the West Valley and all of Phoenix north of Union Hills Drive.

B · Relationships

How it relates to other codes

The codes 623 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Split from · 1999 602 Phoenix Split from 602 in the 1999 three-way division; boundaries later eliminated to form an overlay in 2023.
Overlay · 2023 480 East Valley (Mesa/Tempe/Scottsdale) Co-serves Phoenix metro under the 480/602/623 overlay.
What's changing. Overlay: shares Phoenix-metro geography with 480 and 602 since September 12, 2023.
C · History

How 623 got here

1998-12-18
Arizona Corporation Commission approved a three-way split of 602.
Source: Wikipedia
1999-03-01
623 went into service for the West Valley; permissive dialing began April 1, 1999.
Source: Wikipedia
2023-09-12
Boundaries with 480/602 eliminated; recombined into an overlay complex with mandatory ten-digit dialing.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
326
Prefixes available
474
Thousands-blocks assigned
1,831

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 623 with another code →
Sources
Wikipedia ↗
Area codes 602, 480, and 623
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.