Area Code 840
Area Code 840 is in California
(209 and 350) - (310 and 424)
(341 and 510) - (369 and 707)
(415 and 628) - (408 and 669)
(714 and 657) - (760 and 442)
(818 and 747) - (820 and 805)
(840 and 909) - (916 and 279)
Area Code 840 History:
Area code 840 was officially put into service as an overlay of area code 909. Ten digit dialing (area code + seven digit number) is necessary in the 840/909 overlay because different homes in the same geographic area can have the same seven digit phone number but each would have a different area code.
Counties in California within area code 840 include:
Los Angeles County, Riverside County, and San Bernardino County.
Major cities or places in California within area code 840 include:
Area code 840 serves a portion of eastern Los Angles County, southwest San Bernardino County, and a few communities in Riverside County including the larger cities and communities of Chino, Chino Hills, Claremont, Colton, Diamond Bar, Fontana, Highland, La Verne, Montclair, Ontario, Pomona, Rancho Cucamonga, Redlands, Rialto, San Bernardino, San Dimas, Upland, and Yucaipa in addition to many smaller communities within the area code 840 service area.