Prefix 414-388 — Milwaukee Zone 1, WI

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

414-388 identifies a block of numbers in Milwaukee Zone 1, WI, within the 414 area code. Every US prefix is tied to exactly one rate center; this one is Milwaukee Zone 1.

The rate center lies in the Milwaukee-Waukesha, WI Metropolitan Statistical Area. The serving LATA is 356. Local time follows the Central zone.

Treat the on-screen number as a hint, not evidence — 414-388 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 T-MOBILE USA, INC. (OCN 6529) as the code holder, assigned June 9, 2011. Because 414-388 participates in thousands-block pooling, individual 1,000-number blocks may belong to other carriers than the code holder.

Neighboring prefixes

FAQ

Where is 414-388 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 414-388 numbers?

T-MOBILE USA, INC. 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 414-388 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.