Area Code Atlas

Area code 504 established for all of Louisiana

Area code 504 was established in 1947 as one of the original North American area codes. It initially served the entire state of Louisiana.

NPA 318 split from 504

Area code 318 was assigned in 1957 following a split from the original 504 area code, covering most of Louisiana west of the Mississippi River. This split reduced the territory covered by 504 to southeastern Louisiana.

Area code 225 split from 504

In 1998, area code 225 was created in a split from 504, serving the Baton Rouge area and the western portion of the original numbering plan area. Area code 504 was reduced to the New Orleans metropolitan area and nearby parishes.

NANP-Split of 504 (Louisiana) Numbering Plan Area (NPA)

NPA 225 split from 504

On August 17, 1998, area code 225 was created from a split of area code 504, serving the Baton Rouge metropolitan area and surrounding parishes in southern Louisiana. It was the first new area code in Louisiana in 41 years.

Jeopardy Conservation Procedures Announced for Louisiana NPA 504 and Reminder of the Extended Mandatory Date of 8/16/99 for Cellular Service

Mandatory dialing for the Louisiana 225/504 Wireless Codes; update to PL-123

Urgent Reminder: Mandatory dialing for the Louisiana 225/504 Wireless Codes

504 NPA Split, Creating 985 NPA (Louisiana)

Area code 985 split from 504

In 2001, area code 985 was created in a split from 504, taking over much of southeastern Louisiana, including some suburbs of New Orleans, to the west and north of New Orleans. Several downriver suburbs of New Orleans were also moved to 985 at this time.

504/985 Split - Extended Permissive Dialing for Wireless (Louisiana)

Communities switched back to area code 504 after Hurricane Katrina

In 2007, several communities in lower Plaquemines Parish that had been moved to area code 985 in 2001 were reassigned back to area code 504. This change followed the near-total destruction of local switching facilities due to flooding from Hurricane Katrina, and these communities began receiving service from New Orleans switching facilities.

Communities switched back to 504 from 985 after Hurricane Katrina

In 2007, communities southeast of New Orleans, including areas in lower Plaquemines Parish, were reassigned from area code 985 back to 504. This change was prompted by the destruction of local switching facilities due to Hurricane Katrina, necessitating the use of New Orleans-based infrastructure. Several downriver suburbs that had switched to area code 985 in 2001 were reassigned to 504 in 2007, with affected communities now served by switching facilities in New Orleans.

Louisiana 504/985 RCC and NPA Boundary Realignment

Permissive dialing period for 504 and 985 in reassigned areas

Permissive use of area code 504 alongside 985 began on July 29, 2007, allowing callers to reach the affected southeastern Louisiana communities using either code during the transition.

Mandatory use of area code 504 began for certain communities

Mandatory use of area code 504 began on May 1, 2008, for certain communities that had previously been served by 985. After this date, calls to these areas required dialing 504.

Mandatory use of area code 504 in reassigned areas

Mandatory use of area code 504 began on July 1, 2008, for the southeastern Louisiana communities that had been reassigned from 985, ending the permissive dialing period.

Mandatory ten-digit dialing implemented for area code 504

Mandatory ten-digit dialing was implemented for area code 504 on October 24, 2021, due to the nationwide designation of 988 as a three-digit code for the National Suicide Prevention Lifeline. This change was required to resolve conflicts with existing seven-digit dialing in the area.

Transition to 10-digit dialing for 504 due to 988 implementation

On October 24, 2021, area code 504 transitioned to mandatory ten-digit dialing due to the nationwide implementation of 988 as a dialing code for the National Suicide Prevention Lifeline, which conflicted with existing 7-digit dialing.