Union Bridge, MD — rate center

NANPA rate center & CO code data, current as of July 28, 2026.

The Union Bridge rate center (Maryland) anchors 4 active prefixes under area codes 410, 443, 667. Rate centers, not city limits, are what phone numbers are legally tied to.

The rate center currently carries 4 working prefixes across 4 carriers. 4 prefixes participate in thousands-block pooling, so blocks of 1,000 numbers are shared between carriers.

The rate center belongs to the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area. Routing-wise it sits in LATA 238.

Multiple area codes over one rate center (410/443/667) is the overlay pattern: same geography, different first three digits.

With only 4 prefixes, Union Bridge sits at the small end of Maryland's rate centers — a handful of carrier blocks cover the whole locality, and a number from here is a fairly strong locality signal (before porting is considered).

A Union Bridge prefix on caller ID is a starting point, not proof of origin — numbers travel with their owners and displays can be spoofed. Use official callback numbers for anything sensitive.

Prefixes anchored to Union Bridge

FAQ

What area code is Union Bridge, MD?

Union Bridge is served by 3 area codes — 410, 443, 667 — which overlay the same territory.

How many prefixes does Union Bridge have?

4 active NXX prefixes are anchored to this rate center in NANPA records, held by 4 carriers.

Is a call from a Union Bridge prefix really from Union Bridge?

Not necessarily. The prefix marks where the number block was issued; porting, VoIP and spoofing all detach calls from that geography.