840 Area Code: Riverside, California

The 840 area code is a recent overlay assigned to the Inland Empire region of Southern California, sharing geography with the long-established 951. Riverside, the directory's anchor city for 840, sits at the western edge of the Inland Empire on the Santa Ana River, where the coastal mountains begin to give way to the inland valleys that stretch east toward the desert. The city is home to one of the larger campuses in the University of California system and functions as the commercial center for an extended metro region that has grown rapidly through the past several decades.

A long list of California cities — Anaheim, Bakersfield, Chico, Concord, and others — appears in the directory's records linked to 840 numbers. None of those are inside the 840 footprint. The pattern reflects California's standard high number mobility through porting, prior registration, and the public-record sources that link addresses across cities without filtering on area-code geography. The directory's prefix-level holdings for 840 are still in early stages: we currently document 6 distinct prefixes in detail, a small subset that represents our working coverage rather than a comprehensive count.

Riverside's median age sits notably below the US figure, in the low thirties, a pattern shaped by a younger workforce, a large student population, and the steady inflow of working-age residents priced out of coastal Southern California. Household income runs slightly above the national reading, home values come in roughly twice the US median, and the city's population places Riverside as one of the larger Inland Empire cities.