San Marino is located in the San Gabriel Valley and is neighbored by Pasadena and San Pasqual to the north, East Pasadena and East San Gabriel to the east, Alhambra and San Gabriel to the south, and South Pasadena to the east.
San Marino (aka Chan Marino - thanks to Ngoc for that tidbit) is a tiny, affluent city nestled in the San Gabriel Valley which comes in at number 48 on the list of America's least-affordable places to live. Its homes were mostly built in the second quarter of the 20th century and are in a fairly wide variety of styles-- some are actually pretty low key. Monterey Park may've been envisioned as the "Beverly Hills of East L.A." by its planners, but surely San Marino has more right to the comparison than other Easterly cities and neighborhoods. It has often, on TV and film, subbed as the West Side, East Coast or just a nice, anonymous neighborhood in such timeless, Hollywood classics as Mr & Mrs. Smith, Monster-In-Law, One Hour Photo, American Wedding, Men In Black II, and television episodes of The Fresh Prince of Bel Air, the Office, The West Wing and Alias. Despite the fact that in films and TV it is used to portray genteel, white neighborhoods, in reality most of the population is Chinese-American, which is why people jokingly refer to it as Chan Marino. The population is currently 47% Asian (mostly Taiwanese and Chinese), 44% white (mostly English) and 5% Latino.