Reported (423) XXX-XXXX phone numbers lookup

Area Code 423 History and Coverage

Designated in September 1995, 423 was created by geographic splitting of the 615 numbering plan area of Tennessee. Originally, the boundary followed the dividing line of Central and Eastern time zones placing 423 in the Eastern Time zone area. In 1999, there was a three-way split that created 865 code and divided 423 into two non-contiguous regions which enclose the 865 region.

This unique configuration spans from Tennessee border with Virginia and North Carolina down through Appalachian and Tennessee Valley communities while the region of 865 code separates the two regions of 423. At its periphery, the numbering plan area touches Kentucky 606, Virginia 276, North Carolina 336/743 and 828, Alabama 256/938, Georgia 706/762, and Tennessee 931.

The first efforts to conduct the numbering resource planning were undertaken in September 2001 but due to low demand and reclaiming of some central office codes the process had to be stopped. The introduction of thousands-block number pooling in 2002 postponed further need for additional capacity. However, when the process was continued again in 2022, Tennessee regulators chose 729 as an overlay instead of geographical splitting. Number pool under 729 became available since September 5, 2025.