Prefix 312-312 — Chicago Zone 01, IL
- Area code
- 312
- Prefix (NXX)
- 312
- Rate center
- Chicago Zone 01
- State
- Illinois
- Time zone
- Central
- Code holder
- ONVOY, LLC
- OCN
- 224C
- Pooled
- Yes (thousands-block pooling)
- Assigned
- 2018-01-19
- LATA
- 358
312-312 identifies a block of numbers in Chicago Zone 01, IL, within the 312 area code. Every US prefix is tied to exactly one rate center; this one is Chicago Zone 01.
The rate center lies in the Chicago-Naperville-Elgin, IL-IN Metropolitan Statistical Area. The serving LATA is 358. Local time follows the Central zone.
Treat the on-screen number as a hint, not evidence — 312-312 can be spoofed like any US prefix. If a call feels off, verify through an official callback number and file a complaint with the FCC or FTC.
The assigned code holder is ONVOY, LLC, operating company number 224C, assigned January 19, 2018. This is a pooled prefix — expect numbers within it to be split across more than one carrier in 1,000-number blocks.
Neighboring prefixes
| Prefix | Rate center | Code holder |
|---|---|---|
| 312-308 | Chicago Zone 01 | ILLINOIS BELL TEL CO |
| 312-309 | Chicago Zone 01 | ILLINOIS BELL TEL CO |
| 312-310 | Northbrook | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL |
| 312-313 | Chicago Zone 01 | ONVOY, LLC |
| 312-314 | Hinsdale | NEW CINGULAR WIRELESS PCS, LLC - IL |
| 312-315 | Chicago Zone 01 | NEW CINGULAR WIRELESS PCS, LLC - IL |
FAQ
Where is 312-312 located?
The prefix is assigned to the Chicago Zone 01 rate center in IL, area code 312. It is part of the Chicago-Naperville-Elgin, IL-IN Metropolitan Statistical Area.
Which company owns 312-312 numbers?
ONVOY, LLC holds the code, but the prefix is pooled — individual thousands-blocks can be assigned to other carriers, and numbers may be ported to any provider.
Is a call from 312-312 safe to answer?
The prefix itself says nothing about the caller. Legitimate Chicago Zone 01 businesses and spoofed robocalls can both display it. Never share personal data with an unverified inbound caller.