San Francisco's top-earning zip code spans a cross-section of neighborhoods, including Telegraph Hill, Chinatown, North Beach and the Financial District. Both the City by the Bay's tech prowess and the state's strengthening economy contribute to the area's prosperity.

The rich here are known for their philanthropy, and it's not only formal charities that benefit. Just last month, a wealthy San Francisco real estate developer decided to give back to his community and began leaving $50 and $100 bills across the city, treasure-hunt style, using the Twitter account @HiddenCash.