Prefix 312-486 — Chicago Zone 01, IL

NANPA CO code assignment, current as of July 28, 2026.

Area code
312
Prefix (NXX)
486
Rate center
Chicago Zone 01
State
Illinois
Time zone
Central
Code holder
MCIMETRO ACCESS TRANSMISSION SERVICES LLC
OCN
7229
Pooled
Yes (thousands-block pooling)
Assigned
2004-04-23
LATA
358

312-486 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 — 312-486 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.

NANPA's central-office code records list MCIMETRO ACCESS TRANSMISSION SERVICES LLC (OCN 7229) as the code holder, assigned April 23, 2004. Because 312-486 participates in thousands-block pooling, individual 1,000-number blocks may belong to other carriers than the code holder.

Neighboring prefixes

Prefixes adjacent to 312-486
PrefixRate centerCode holder
312-483 Chicago Zone 01 T-MOBILE USA, INC.
312-484 Chicago Zone 01 SPOK, INC.
312-485 Chicago Zone 01 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL
312-487 Chicago Zone 01 METROPCS, INC.
312-488 Chicago Zone 01 LEVEL 3 COMMUNICATIONS, LLC - IL
312-489 Chicago Zone 01 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL

FAQ

Where is 312-486 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 312-486 numbers?

MCIMETRO ACCESS TRANSMISSION SERVICES 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 312-486 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.