North American Numbers Source-cited · ownership disclosed
Area code
773
In service
United States · since 1996

Chicago (Outer Neighborhoods)

Created on October 12, 1996 by splitting from 312, area code 773 serves the areas of the city of Chicago outside the downtown Loop.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Chicago (Outer Neighborhoods)
Type
geographic
Status
in service
In service since
1996
Projected exhaust
2046 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 773 is

The city of Chicago outside the central Loop - the outer/residential neighborhoods surrounding downtown.

Communities served wholly or partly by 773:

Chicago (neighborhoods outside the Loop)

Covers Chicago city proper except the downtown core (which is 312); 773 geographically surrounds 312.

B · Relationships

How it relates to other codes

The codes 773 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 312 Chicago (The Loop / Downtown) Split from 312 on Oct 12, 1996; 773 took the city outside downtown.
Overlay · 2009 872 Chicago (Citywide Overlay) 872 overlaid the combined 312+773 area on Nov 7, 2009.
What's changing. Overlaid by 872 (all-services overlay) since Nov 7, 2009; shares its numbering-plan area with 312.
C · History

How 773 got here

1996-10-12
Established by split from 312 to serve Chicago neighborhoods outside downtown.
Source: Wikipedia - Area code 773
2009-11-07
Overlay 872 went into service across the 312/773 area.
Source: Wikipedia - Area code 773
D · Capacity

How full it is

Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
3,156

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

Compare 773 with another code →
Sources
Wikipedia ↗
Area code 773
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.