858 Area Code: San Diego, California

San Diego's northern neighborhoods and the inland mesas above the city sit inside the 858 area code, with the city of San Diego itself as the primary city in the directory's records. The 858 footprint covers La Jolla, University City, Mira Mesa, Rancho Bernardo, and the broader stretch of the city that runs north from Mission Bay up toward the Carmel Valley and into the older planned communities of Scripps Ranch and Poway. The corridor includes a substantial concentration of biotechnology, defense, and university research employment, anchored by UC San Diego and the surrounding research institutions.

Other California cities — Anaheim, Bakersfield, Chico, Concord, and many more — turn up in the directory's records linked to 858 numbers. None of those are inside the 858 footprint. The recurrence reflects California's standard high number mobility through porting, prior registration, and the public-record sources that link addresses across cities. The directory currently documents 361 distinct prefixes within 858 in detail, a working subset of the active prefix population that the code carries.

San Diego's median household income sits well above the US figure, supported by the city's defense, biotech, and tourism economies. Home values run roughly three times the national median, in line with broader Southern California coastal pricing. The city's population is among the largest in California, and the median age skews a few years younger than the country at large. Within the broader city, the 858 footprint trends toward a concentration of research and university employment.