Area codes 909 and 840 are telephone area codes in the North American Numbering Plan for the far-eastern part of Los Angeles County southwestern San Bernardino County, and a small portion of Riverside County in the U.S. state of California. Area code 909 was created on November 14, 1992, in an area code split of 909, and 840 was added to the numbering plan area to form an overlay complex effective February 23, 2021. While most of western Riverside County now uses Area code 951, some residents in Eastvale and Corona were allowed to keep the 909 area code after the split in 2004.