Prefix 312-530 — Chicago Zone 01, IL

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

Area code
312
Prefix (NXX)
530
Rate center
Chicago Zone 01
State
Illinois
Time zone
Central
Code holder
STRATUS NETWORKS
OCN
495J
Pooled
Yes (thousands-block pooling)
Assigned
2020-07-28
LATA
358

Numbers in the 312-530 prefix are registered to the Chicago Zone 01 rate center in IL, inside area code 312. The prefix is the second block of a ten-digit US number (312-530-XXXX) and pins the number to a billing locality.

NANPA's central-office code records list STRATUS NETWORKS (OCN 495J) as the code holder, assigned July 28, 2020. Because 312-530 participates in thousands-block pooling, individual 1,000-number blocks may belong to other carriers than the code holder.

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.

Spoofing means this prefix on your screen doesn't guarantee a Chicago Zone 01 caller. Verify independently before trusting a request for money or data.

Neighboring prefixes

Prefixes adjacent to 312-530
PrefixRate centerCode holder
312-527 Chicago Zone 01 ILLINOIS BELL TEL CO
312-528 Chicago Zone 01 ILLINOIS BELL TEL CO
312-529 Chicago Zone 01 AT&T - LOCAL
312-531 Hinsdale NEW CINGULAR WIRELESS PCS, LLC - IL
312-532 Chicago Zone 01 T-MOBILE USA, INC.
312-533 Chicago Zone 01 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL

FAQ

Where is 312-530 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 312-530 numbers?

STRATUS NETWORKS 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 312-530 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.