North American Numbers Source-cited · ownership disclosed
Area code
630
In service
United States · since 1996

West Chicago Suburbs (DuPage County)

Created in the three-way split of 708, in service August 3, 1996, serving Chicago's western suburbs centered on DuPage County. It has been overlaid by 331 since 2007.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
West Chicago Suburbs (DuPage County)
Type
geographic
Status
in service
In service since
1996
Projected exhaust
2080 Q1

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 630 is

Majority of DuPage County, parts of northwest Cook County, southern Kane County, northern Will County, and exurban Kendall County.

Communities served wholly or partly by 630:

AuroraNapervilleWheatonDowners GroveBolingbrookLombardElmhurstGlen EllynOak BrookHinsdale

Representative subset (~80+ suburbs).

B · Relationships

How it relates to other codes

The codes 630 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 · 1996 708 South/Near-West Chicago Suburbs 630 split off from 708 (three-way split), in service Aug 3, 1996.
Overlay · 2007 331 West Chicago Suburbs (overlay of 630) 331 overlaid 630 on Oct 7, 2007; mandatory ten-digit dialing.
Related · 1996 847 North/Northwest Chicago Suburbs Sibling code from the same 708 three-way split, covering north suburbs.
What's changing. Overlaid by 331 since Oct 7, 2007; ten-digit dialing required.
C · History

How 630 got here

1996-08-03
630 in service via three-way split of 708 (west suburbs).
Source: Wikipedia - Area codes 630 and 331
2007-10-07
331 overlay took effect over 630 (ten-digit dialing).
Source: Wikipedia - Area codes 630 and 331
D · Capacity

How full it is

Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
2,701

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

Compare 630 with another code →
Sources
Wikipedia ↗
Area codes 630 and 331
Illinois Commerce Commission ↗
Chronological History of Area Code Relief in Illinois
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.