Area codes 678 and 470 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. State of Georgia in the Atlanta metropolitan area. Both area codes are assigned in an overlay plan to a combined numbering plan area (NPA) consisting of 404 (Atlanta and its suburbs inside Interstate 285) and 770 (Atlanta suburbs and exurbs outside of 285).
Telephone numbers in area code 678 were first assigned to customers signing up for new telephone service on January 15, 1998. On September 2, 2001, area code 470, chosen by the Georgia Public Service Commission, was added to the overlay of area codes 404, 770, and 678 Telephone numbers from the NPA were assigned after exhaustion of area code 678.
Although ten-digit dialing was used in the Atlanta area since area code 770 was introduced in 1995, it was not until January 1, 1998, when 678 was implemented, that ten-digit dialing finally became required across the entire metro area.
All central office prefixes of numbering plan area 404 are assigned to service providers, the last having been issued in October 2013. Prefixes 678 and 770 have also all been allocated, leaving only 470 central office codes available, although previously-used numbers are always available for reassignment to new customers. Despite existing for decades before this change, the largest customer using area code 470 is Kennesaw State University in Kennesaw, which was forced to change hundreds of telephone numbers when the Georgia Board of Regents forced schools in the University System of Georgia to implement internal telephone systems, and the FCC failed to make local number portability applicable to businesses and government, allowing AT&T to refuse KSU to take its numbers to the new provider. Kennesaw State University opted to use 470-578 (KSU) as their number prefix for the new phone numbers, outside of the normal geographical calling area for Kennesaw; 470-578 numbers are based in Atlanta Northeast and Kennesaw State University is located in the Atlanta Northwest calling area.
The entire metro Atlanta region with area codes 404, 770, 678, and 470, is a local calling area, one of the largest in the United States, without long-distance charges for calls between area codes. All calls in the area are dialed with ten digits. In addition, calls to and from the Atlanta area with area codes 706 and 762, which serve most of north Georgia, are also local calls.
Area codes 678 and 470 serve the counties of Barrow, Bartow, Butts, Carroll, Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Hall, Haralson, Henry, Heard (part with area codes 706 and 762), Lamar, Meriwether (part with area codes 706 and 762), Newton, Oconee, Paulding, Pike, Polk, Rockdale, Spalding, and Walton.
- North American Numbering Plan Administration, NPA 470 To Overlay NPAs 404, 678, and 770, Planning Letter PL-269 (March 28, 2001)
- "North America Numbering Plan Planning Letter" (PDF). Nanpa.com. Retrieved 2012-09-29.
- "No more 404, 678 area codes given in Atlanta". M.ajc.com. Retrieved 11 July 2018.
- Chow, Ray. "Local calling guide: NPA-NXX search". Localcallingguide.com. Retrieved 2017-01-20.
- Chow, Ray. "Local calling guide: Rate centre information". Localcallingguide.com. Retrieved 2017-01-20.
|West: 256/938||678/470 (overlaying 404 and 770)||East: 706/762|
|South: 478, 706/762|
|Alabama area codes: 205/659, 251, 256/938, 334|