Prefix 414-310 — Milwaukee Zone 1, WI

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

Area code
414
Prefix (NXX)
310
Rate center
Milwaukee Zone 1
State
Wisconsin
Time zone
Central
Code holder
ONVOY, LLC - WI
OCN
225C
Pooled
Yes (thousands-block pooling)
Assigned
2017-08-09
LATA
356

The 414-310 prefix belongs to area code 414 and is anchored to the Milwaukee Zone 1 rate center (WI). In NANP terms, the prefix — or NXX — determines the rate center a number is billed against.

Milwaukee Zone 1 is part of the Milwaukee-Waukesha, WI Metropolitan Statistical Area. For routing purposes it sits in LATA 356. Numbers here keep Central time.

The assigned code holder is ONVOY, LLC - WI, operating company number 225C, assigned August 9, 2017. This is a pooled prefix — expect numbers within it to be split across more than one carrier in 1,000-number blocks.

Caller ID showing 414-310 is not proof the call came from Milwaukee Zone 1: spoofing and porting both detach numbers from their origin. To verify a caller, hang up and dial the organization's published number, and report suspicious calls to the FTC.

Neighboring prefixes

Prefixes adjacent to 414-310
PrefixRate centerCode holder
414-307 Milwaukee Zone 1 LEVEL 3 COMMUNICATIONS, LLC - WI
414-308 Milwaukee Zone 1 PAETEC ITEL, LLC
414-309 Milwaukee Zone 1 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WI
414-312 Milwaukee Zone 1 LEVEL 3 COMMUNICATIONS, LLC - WI
414-313 Milwaukee Zone 1 UNITED STATES CELLULAR - WI
414-314 Milwaukee Zone 1 SPOK, INC.

FAQ

Where is 414-310 located?

The prefix is assigned to the Milwaukee Zone 1 rate center in WI, area code 414. It is part of the Milwaukee-Waukesha, WI Metropolitan Statistical Area.

Which company owns 414-310 numbers?

ONVOY, LLC - WI 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 414-310 safe to answer?

The prefix itself says nothing about the caller. Legitimate Milwaukee Zone 1 businesses and spoofed robocalls can both display it. Never share personal data with an unverified inbound caller.