Area codes 909 and 840

Area codes 909 and 840 are telephone area codes in the North American Numbering Plan (NANP) for the far-eastern part of Los Angeles County and southwestern San Bernardino County in the U.S. state of California.

Numbering plan areas in California (blue) and border states. Area codes 840 and 909 are shown in red.

Area code 909 was split from area code 714 on November 14, 1992. By August 1993, dialing of the area code became mandatory.

On August 26, 1999, the NANPA approved a request by the California Public Utilities Commission for a 2-phase split/overlay plan to provide area code relief for 909.[1] In phase one, nearly all of western Riverside County was to be split off from 909 into area code 951 on September 9, 2000. Meanwhile, preparation for phase two was to have begun on February 12, 2000 with 1+10-digit permissive dialing being introduced for the remainder of 909 in advance of a new 752 overlay NPA with an in-service date set for February 10, 2001. (Because of the nationwide outcry and protests at the time regarding the large number of area code splits as well as outrage over the requirement of 10-digit dialing in regions now served by recently introduced new-fangled "overlay" area codes, the CPUC decided they would mitigate consumers' pain by implementing a series of 2-phase "split/overlay" relief plans so that an "equal amount of inconvenience" would be experienced by each group: those who were losing their area code would get to keep 7-digit dialing for calls within their new area code, while the rest got to keep their original area code but would be required to dial 1+10 digits for all calls, be they local or long distance.) However, with the implementation of 1000-block number pooling, both portions of the 909 split/overlay were cancelled before either phase could be implemented. (Similar plans were being considered to provide relief to the 310, 415, 510, 760 and 818 area codes as well; however, due to number rationing, all were postponed indefinitely and later permanently cancelled.)

Nevertheless, even with numbering conservation measures in place, it was determined in 2003 that 909 would indeed require relief.[2] As such (and exactly as had been originally planned in September of 2000), western Riverside County was split off from 909 into area code 951 on July 17, 2004. (909 continued to serve small portions of Corona, Riverside, Moreno Valley, and the entire city of Calimesa, all of which are in Riverside County, as well as small portions of eastern Los Angeles and northern Orange Counties; area code 752 was returned to the numbering pool to be reassigned at a later date.)

On July 23, 2019, the California Public Utilities Commission approved an all-services overlay for area code 909 with the new area code 840, efffective February 23, 2021. A permissive dialing period was implemented from July 2020 to January 2021. While 840 numbers are issued to new subscribers, those with 909 numbers retain them.[3]

840 was California's 36th area code. With its establishment, one half of California's 24 geographic numbering plan areas (NPAs) consisted of overlays, while the other twelve remained single-code NPAs.