Area Code Atlas

NPA 810 assigned for TWX service

In the 1960s, area code 810 was assigned as a Service Access Code (SAC) for TWX service, serving every U.S. point west of the Mississippi River.

NPA 810 assigned for TWX service

Area code 810 was assigned in the 1960s as a Service Access Code for TWX service, serving every U.S. point west of the Mississippi River. The code was decommissioned for telex use in 1981.

Traffic Routing Guide issued

The Traffic Routing Guide, which included information on TWX area codes such as 510 and 810, was issued on November 29, 1965.

Traffic Routing Guide revised and issued

A revised edition of the Traffic Routing Guide, covering TWX area codes including 510 and 810, was issued on September 12, 1975.

NPA 810 split from 313

Area code 810 was created in 1993 as a split from 313, taking over much of the territory outside of Monroe, Wayne, and Washtenaw counties in southeastern Michigan.

NPA 810 split from 313

Area code 810 was created on December 1, 1993, as a geographic split from area code 313. The new code covered east-central Michigan, including Flint, Lapeer, Port Huron, and surrounding counties, while 313 continued to serve Detroit and adjacent areas. A permissive dialing period followed the split.

Mandatory dialing for 810 and 313 after split

The permissive dialing period following the split of area code 313 ended on August 10, 1994. After this date, callers were required to use the correct area code—either 810 or 313—when dialing numbers in the affected regions.

End of permissive dialing between 313 and 810

The permissive dialing period ended on August 10, 1994, requiring callers to use the new area code 810 for numbers in the new numbering plan area, while 313 remained for the rest of southeastern Michigan.

NANP-Split of 810 (Michigan) Numbering Plan Area (NPA)

NPA 248 split from 810

Area code 248 was created in 1997 as a geographic split from area code 810, serving Oakland County and parts of Wayne County in Michigan. The split was implemented to address central office code exhaustion in the region, reducing the territory of 810.

NPA 248 split from 810

Area code 248 was introduced for Oakland County, Michigan, with a permissive dialing period beginning May 10, 1997. This split relieved 810, which continued to serve surrounding areas.

Extraordinary NPA-Specific Jeopardy Conservation Procedures Announced for 810 NPA (Michigan)

NANP - Overlay of 810 Numbering Plan Area (NPA) with 586 NPA - Michigan

810 NPA Split, Creating 586 NPA (Michigan)

NPA 586 split from 810

Area code 586 was created in March 2001 by splitting from area code 810 to serve Macomb County, including Mt. Clemens, Roseville, Warren, and Utica. Wireless central office codes in rate centers moving to the new NPA were permanently grandfathered.

810 / 586 NPA Split - Wireless NXX Grandfathering (Michigan)

810 / 586 NPA Split (Michigan) - Wireless NXX Grandfathering

NPA 586 split from 810

Area code 586 was created on September 22, 2001, as a split from area code 810, serving most of Macomb County, Michigan. The split was implemented after an initial proposal to overlay 586 on 810 was rejected due to opposition to ten-digit dialing.

Mandatory dialing for NPA 586 and 810

Permissive dialing for area code 810 continued until March 23, 2002, after which mandatory dialing of the new area code 586 was required for calls within its territory.

Transition to ten-digit dialing in area code 810

Area code 810 transitioned to mandatory ten-digit dialing by October 24, 2021, due to the nationwide designation of 988 as the National Suicide Prevention Lifeline dialing code, which conflicted with existing seven-digit dialing in the area. This change affected all customers in the 810 area.