Area Code Atlas

NPA 901 split to create 615

Tennessee was divided into two numbering plan areas in 1954. Area code 615 was assigned to the eastern two-thirds of the state, while 901 continued to serve West Tennessee. The split was a flash-cut, reducing 901 to West Tennessee and assigning 615 to Middle and East Tennessee.

NANP-SPLIT OF 615 (TENNESSEE) NUMBERING PLAN AREA (NPA)

NPA 423 split from 615

In 1995, area code 423 was created from the eastern portion of area code 615, including Knoxville, Chattanooga, and the Tri-Cities. This was the first new area code in Tennessee in 41 years and was implemented to address number exhaustion in East Tennessee.

NPA 423 split from 615

Area code 423 was created in September 1995 from a split of 615, assigning most of the eastern portion of 615—including Chattanooga, Knoxville, and the Tri-Cities—to the new code. The boundary largely followed the division between the Eastern and Central Time Zones.

NANP-Split of 615 (Tennessee) Numbering Plan Area (NPA)

NPA 931 split from 615

Area code 931 was created in September 1997 from a split of 615, taking over most of the western, southern, and eastern portions of the old 615 territory, including Clarksville, Cookeville, Columbia, and Tullahoma. 615 was reduced to the Nashville metropolitan area.

NPA 931 split from 615

Area code 931 was created by splitting from area code 615 on September 15, 1997. This split reduced the numbering plan area of 615 to the inner ring of Nashville, while 931 serves a horseshoe-shaped region of twenty-eight counties in Middle Tennessee excluding Nashville.

Mandatory dialing for NPA 931 and 615

Permissive dialing for area codes 931 and 615 ended on January 15, 1998. After this date, callers were required to use the correct area code for calls within Middle Tennessee.

Permissive dialing of 615 continued after 931 split

Permissive dialing of area code 615 continued across Middle Tennessee until January 15, 1998, allowing callers to use either 615 or 931 during the transition period following the split.

NANPA projects 615 to exhaust in 2Q 2015

NANPA updated its projections on March 9, 2012, estimating that area code 615 would exhaust its supply of numbers in the second quarter of 2015, prompting the need for relief planning.

Overlay relief planned for NPA 615 with new NPA 629

Area code 629 was approved on October 21, 2013, as an overlay for the 615 numbering plan area. This was Tennessee's first overlay, intended to provide additional numbering resources without requiring existing customers to change their numbers.

TRA approves overlay relief for 615

The Tennessee Regulatory Authority approved the all-services distributed overlay method of relief for the 615 area code on October 23, 2013. This decision set the stage for the introduction of area code 629 to address number exhaustion in the Nashville region.

NPA 629 overlay on 615 announced

NPA 629 to Overlay NPA 615 (Tennessee)

Permissive dialing begins for 629 overlay

Permissive dialing for the new 629 overlay began on July 26, 2014, allowing calls to be completed using either seven or ten digits within the 615/629 region. This transition period was intended to prepare residents for mandatory ten-digit dialing.

Mandatory ten-digit dialing for 615/629

Ten-digit dialing became mandatory in the 615/629 overlay region in February 2015, requiring callers to use the area code for all local calls. This change was necessary to accommodate the new overlay and ensure sufficient numbering resources.

Mandatory ten-digit dialing begins for overlay NPA 629

Mandatory ten-digit dialing began in late February 2015 for the 615/629 overlay complex, requiring callers to dial the area code for all local calls.

NPA 629 overlays 615

Area code 629 was introduced in spring 2015 as an overlay to 615, providing additional numbering resources for the rapidly growing Nashville metropolitan area. The overlay allowed existing customers to retain their numbers while new numbers could be assigned with the new code.

NPA 629 overlays 615

Area code 629 was introduced as an overlay to the 615 region in spring 2015, providing additional numbering resources for the rapidly growing Nashville metropolitan area. New numbers in the region began to be assigned with the 629 code.