Area Code Atlas

NPA 405 introduced as original Oklahoma area code

Area code 405 was put into service in 1947 as one of the original North American area codes, covering the entire state of Oklahoma.

NPA 918 split from 405 for northeastern Oklahoma

On January 1, 1953, area code 918 was assigned to northeastern Oklahoma, splitting from the original 405 area code. After this split, 405 covered the remainder of the state except for the northeast.

Declaration of Jeopardy Situation in NPA 405 (Oklahoma)

NANP-Split of 405 (Oklahoma) Numbering Plan Area (NPA)

NANP-Split of  405 (Oklahoma) Numbering Plan Area (NPA)

NPA 580 split from 405 for southern and western Oklahoma

Area code 580 was created by splitting from 405 on November 1, 1997. The new code took over most of southern and western Oklahoma, while 405 was retained for the urban core of central Oklahoma, including Oklahoma City. This split made 580 one of the most thinly populated area codes in the nation.

NPA 405 projected to exhaust by 2021

In October 2017, area code 405 was projected to exhaust by the second quarter of 2021. This projection led to planning for relief measures in central Oklahoma.

NPA 572 announced as overlay for 405

On January 9, 2020, it was announced that area code 572 would overlay area code 405 in central Oklahoma to provide additional numbering resources.

NPA 572 overlay on 405 announced

NPA 572 to Overlay NPA 405 (Oklahoma)

Ten-digit dialing becomes mandatory for 405/572 overlay complex

In January 2021, ten-digit dialing became mandatory in central Oklahoma due to the implementation of the 405/572 overlay complex.

NPA 572 overlays 405 in central Oklahoma

Area code 572 was activated as an overlay for 405 in central Oklahoma in 2021, providing additional numbering resources for the Oklahoma City metropolitan area. Existing 405 numbers were not changed.