Area Code Atlas

NPA 314 introduced as one of Missouri's original area codes

In 1947, area code 314 was introduced as one of the original area codes assigned to Missouri under the North American Numbering Plan. It initially covered the eastern part of the state, including St. Louis.

Original Missouri area codes assigned

Missouri was divided into two original area codes, 314 for the eastern part and 816 for the western part, as part of the initial North American Numbering Plan in 1947.

NANP-SPLIT OF 314 (MISSOURI) NUMBERING PLAN AREA (NPA)

NPA 573 split from 314

Area code 573 was created on January 7, 1996, as a geographic split from area code 314. The new code served most of eastern Missouri outside the St. Louis metropolitan area, including Jefferson City and Columbia, while 314 was retained for St. Louis and nearby communities.

Permissive dialing period for 573 and 314

A permissive dialing period began on January 7, 1996, allowing calls to be completed using either 314 or 573 for affected numbers. This transition period lasted until July 7, 1996, to ease the change for customers.

Permissive dialing period ends for 573 split from 314

The permissive dialing period for the 573 split from 314 ended on July 7, 1996. After this date, calls had to be dialed using the correct area code.

Jeopardy Declared for 314 in Missouri

Geographic Split of 314 (Missouri) Numbering Plan Area (NPA)

Update of Jeopardy Procedures for Numbering Plan Area (NPA) 314 in Missouri; this notice updates PL-147

NPA 636 split from 314

Area code 636 was introduced on May 22, 1999, as a result of a geographic split from 314. The split was implemented to address number exhaustion in the St. Louis area, with 636 assigned to the western suburbs and surrounding counties.

Overlay of area code 557 on 314

Area code 557 was overlaid on the 314 region in August 2022 to provide additional numbering capacity as existing numbers neared exhaustion.

Permissive dialing period ends for 636 split from 314

The permissive dialing period for the 636 split from 314 ended on February 26, 2000. After this date, calls had to be dialed using the correct area code.

Overlay relief plan for 314 approved, assigning 557 as overlay

On October 24, 2000, the Missouri Public Service Commission approved a relief plan for the 314 area code, assigning 557 as an all-services overlay for the same geographic area. The overlay was intended to address projected number exhaustion.

NPA 557 overlay on 314 announced

New NPA 557 to Overlay NPA 314 (Missouri)

NPA 557 Overlay of NPA 314 Implementation Date and Dialing Plan Change (Missouri)

Implementation of 557 overlay for 314 postponed indefinitely

On September 25, 2001, the Missouri Public Service Commission announced the indefinite suspension of the implementation of the 557 overlay for the 314 area code, citing conservation measures and a lack of immediate need for additional numbering resources.

Suspension of the 314 NPA Relief (Missouri)

Mandatory ten-digit dialing begins for 314

On October 24, 2021, mandatory ten-digit dialing was implemented for area code 314. This change was required due to the nationwide designation of 988 as the three-digit code for the National Suicide Prevention Lifeline and to prepare for the 557 overlay, which conflicted with existing 7-digit dialing in the area.

NPA 557 overlay on 314 announced

NPA 557 to Overlay NPA 314 (Missouri)

NPA 557 overlay activated for 314

On August 12, 2022, area code 557 was activated as an all-services overlay for the 314 area code region, providing additional numbering resources for St. Louis and its inner suburbs as 314 neared exhaustion. Both area codes now serve the same geographic area, and ten-digit dialing is required.