39. Blackhawk, California (Average Household Income: $272,940)

Blackhawk is an unincorporated planned community east of Danville and Oakland. It has a country club, two golf courses, a sports complex, restaurants, and the adjacent Blackhawk Plaza shopping center.

Governed by county rules, regulations, and an HOA, Blackhawk has round-the-clock security. Additional law enforcement contracted through the Contra Costa County Sheriff’s Office is provided to residents, and paid for by HOA dues.