Area Code 678 — Georgia (overlay with area code 770)
Covers Marietta, Roswell, Alpharetta, Sandy Springs, and Lawrenceville and surrounding areas in Georgia (GA).
Time zone: Eastern (ET) | Established: 1998
Where Is Area Code 678?
Area code 678 serves suburban Atlanta as an overlay sharing coverage with area code 770. Introduced in 1998 as an overlay to area code 770, it shares the same geographic footprint — new phone numbers in the region may be assigned either code. The area is home to approximately 3.5 million people and falls within the Eastern (ET) time zone.
Marietta is the largest city in the 678 area code and serves as the economic and cultural center of the region. Other notable communities include Roswell, Alpharetta, and Sandy Springs, each contributing to the area’s mix of residential, commercial, and cultural activity. The urban and suburban character of the area supports a diverse economy spanning healthcare, technology, education, retail, and professional services.
The introduction of area code 678 as an overlay meant that residents and businesses in the region transitioned to mandatory 10-digit dialing for all local calls. Unlike an area code split — which reassigns existing numbers to a new code — an overlay keeps all existing 770 numbers intact and simply adds 678 as a second option for new assignments. Georgia currently uses 9 area codes to serve its residents.
Major Cities and Communities in the 678 Area Code
The following cities and communities are served by area code 678:
- Marietta
- Roswell
- Alpharetta
- Sandy Springs
- Lawrenceville
Area Code 678 Details
| State | Georgia (GA) |
| Time Zone | Eastern (ET) (UTC-5 / UTC-4 (DST)) |
| Year Established | 1998 |
| Overlay Code | Yes |
| Approximate Population Served | 3,500,000 |
| Region | Covers suburban Atlanta as an overlay sharing coverage with area code 770 |
Interesting Facts About Area Code 678
- Area code 678 was introduced in 1998 as an overlay for area code 770, meaning both codes serve the exact same geographic area in Georgia.
- Area code 678 serves approximately 3.5 million people, making it one of the more heavily used area codes in the country.
- Because 678 is an overlay code, all calls in the region require 10-digit dialing — you must dial the area code even for local calls.
Related Area Codes
Other Georgia area codes: 229, 404, 470, 478, 706, 762, 770, 912
Alabama: 205, 256
Florida: 904, 386
North Carolina: 828, 704
South Carolina: 864, 803
Tennessee: 423, 615
Frequently Asked Questions
What cities use area code 678?
Area code 678 serves Marietta, Roswell, Alpharetta, Sandy Springs, and Lawrenceville and surrounding communities in Georgia.
What time zone is area code 678?
Area code 678 is in the Eastern (ET) time zone (UTC-5 / UTC-4 (DST)).
Is 678 a toll-free number?
No, area code 678 is not a toll-free number. It is a geographic area code assigned to Georgia. Toll-free area codes include 800, 888, 877, 866, 855, 844, and 833.
When was area code 678 established?
Area code 678 was established in 1998.
Is area code 678 an overlay code?
Yes, area code 678 is an overlay code that shares geographic coverage with area code 770 in Georgia. Both codes serve the same area.
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