Chicago Zone 07, IL — rate center
- State
- Illinois
- Active prefixes
- 107
- Carriers
- 16
- Pooled prefixes
- 86
- LATA
- 358
- Metro area
- Chicago-Naperville-Elgin, IL-IN MSA
The Chicago Zone 07 rate center (Illinois) anchors 107 active prefixes under area codes 312, 773, 872. Rate centers, not city limits, are what phone numbers are legally tied to.
107 central-office prefixes are currently anchored to this rate center across 16 carriers. 86 prefixes participate in thousands-block pooling, so blocks of 1,000 numbers are shared between carriers.
The rate center belongs to the Chicago-Naperville-Elgin, IL-IN Metropolitan Statistical Area. Routing-wise it sits in LATA 358.
Multiple area codes over one rate center (312/773/872) is the overlay pattern: same geography, different first three digits.
At 107 prefixes — a ceiling of 1,070,000 numbers — Chicago Zone 07 is one of Illinois's heavyweight rate centers.
Treat this data as geography of the number, not of the caller: porting, VoIP and caller-ID spoofing all detach the two. When a call matters, hang up and call back through an official number.
Prefixes anchored to Chicago Zone 07
| Prefix | Code holder | Pooled |
|---|---|---|
| 312-287 | T-MOBILE USA, INC. | Yes |
FAQ
What area code is Chicago Zone 07, IL?
Chicago Zone 07 is served by 3 area codes — 312, 773, 872 — which overlay the same territory.
How many prefixes does Chicago Zone 07 have?
107 active NXX prefixes are anchored to this rate center in NANPA records, held by 16 carriers.
Is a call from a Chicago Zone 07 prefix really from Chicago Zone 07?
Not necessarily. The prefix marks where the number block was issued; porting, VoIP and spoofing all detach calls from that geography.