Nob Hill is a neighborhood in San Francisco centered on the intersection of California Street and Powell Street. It is one of San Francisco's 44 hills and one of its original "Seven Hills". Prior to the 1850s Nob Hill was called California Hill. It was renamed after the Central Pacific Railroad's Big Four - called the Nobs - built mansions there. Nob Hill is an affluent district home to many of the city's upper-class families as well as a large young urban professional population and a growing Chinese immigrant population from Chinatown to the east. Nob is a disparaging British slang abbreviation of "noble/nobility" referring to the newly rich. The location is also derisively referred to as Snob Hill. The intersection of California and Powell streets is the location of two of its four well-known and most expensive hotels.