North American Numbers Source-cited · ownership disclosed
Area code
667
In service
United States · since 2012

Baltimore (overlay)

The second overlay of the 410/443 region, covering the same eastern-Maryland territory. It entered service March 24, 2012 to relieve renewed number exhaustion.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Baltimore (overlay)
Type
geographic
Status
in service
In service since
2012
Projected exhaust
2036 Q1

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 667 is

Eastern Maryland: same footprint as 410 and 443 — Baltimore metro plus the Eastern Shore counties..

Communities served wholly or partly by 667:

BaltimoreAnnapolisTowsonColumbiaSalisburyBel AirOcean City

Same geography as 410 and 443 — an overlay, not a distinct area.

B · Relationships

How it relates to other codes

The codes 667 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Overlay · 2012 410 Baltimore 667 overlays the 410 base code.
Overlay · 2012 443 Baltimore (overlay) 667 overlays 443 as well; all three share the region.
Related · 1991 301 Western/Southern Maryland (D.C. suburbs) The 410 region 667 overlays originally split from 301.
What's changing. Second overlay of the 410/443/667 complex; ten-digit dialing mandatory.
C · History

How 667 got here

2012-03-24
Area code 667 entered service as a third overlay for eastern Maryland; ten-digit dialing already in effect.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
466
Prefixes available
334
Thousands-blocks assigned
3,954

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 667 with another code →
Sources
Wikipedia ↗
Area code 667
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.