North American Numbers Source-cited · ownership disclosed
Area code
678
In service
United States · since 1998

Atlanta metro (overlay)

Georgia's first overlay area code, introduced in 1998 over the entire Atlanta metropolitan region served by 404 and 770. It shares geography with later overlays 470 and 943.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Atlanta metro (overlay)
Type
geographic
Status
in service
In service since
1998
Projected exhaust
2039 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 678 is

Entire Atlanta metropolitan region — the combined 404 (inside I-285) and 770 (outside I-285) numbering plan area..

Communities served wholly or partly by 678:

AtlantaMariettaRoswellAlpharettaLawrencevilleDecatur

Same footprint as 404 and 770 combined; no distinct geography of its own.

B · Relationships

How it relates to other codes

The codes 678 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 · 1998 404 Atlanta Overlays 404 (urban core).
Overlay · 1998 770 Atlanta suburbs Overlays 770 (suburban ring).
Overlay · 2001 470 Atlanta metro (overlay) Co-overlay of same region; added when 678 exhausted.
Overlay · 2022 943 Atlanta metro (overlay) Co-overlay of same region.
What's changing. Overlay. Part of the five-code Atlanta metro overlay complex (404/470/678/770/943). All 678 prefixes are fully allocated.
C · History

How 678 got here

1998-01-01
First overlay in Georgia, placed over 404 and 770; ten-digit dialing became mandatory across the metro (some sources cite Jan 15, 1998).
Source: Wikipedia
2001-09-02
Area code 470 added to the same overlay after 678 numbers were exhausted.
Source: Wikipedia
2022-03-15
Area code 943 added as a further overlay of the same region.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
4,002

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

Compare 678 with another code →
Sources
Wikipedia ↗
Area code 678
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.