Prefix 312-723 — Chicago Zone 01, IL

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

Area code
312
Prefix (NXX)
723
Rate center
Chicago Zone 01
State
Illinois
Time zone
Central
Code holder
NEW CINGULAR WIRELESS PCS, LLC - IL
OCN
6534
Pooled
Yes (thousands-block pooling)
Assigned
2016-11-28
LATA
358

312-723 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 — 312-723 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 NEW CINGULAR WIRELESS PCS, LLC - IL, operating company number 6534, assigned November 28, 2016. This is a pooled prefix — expect numbers within it to be split across more than one carrier in 1,000-number blocks.

Neighboring prefixes

Prefixes adjacent to 312-723
PrefixRate centerCode holder
312-720 Chicago Zone 01 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL
312-721 Chicago Zone 01 T-MOBILE USA, INC.
312-722 Chicago Zone 01 PAETEC ITEL, LLC
312-724 Chicago Zone 01 BANDWIDTH.COM CLEC, LLC - IL
312-725 Chicago Zone 01 BANDWIDTH.COM CLEC, LLC - IL
312-726 Chicago Zone 01 ILLINOIS BELL TEL CO

FAQ

Where is 312-723 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 312-723 numbers?

NEW CINGULAR WIRELESS PCS, LLC - IL 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 312-723 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.