Belvedere is a residential incorporated city located on the San Francisco Bay in Marin County, California, United States. Consisting of two islands and a lagoon, it is connected to the Tiburon Peninsula by two causeways. At the 2020 census, the population was 2,126. The per capita income of Belvedere residents in 2000 was $250,000, but currently the average income is $283,000, making it one of the highest-income cities in California and the eighth highest-income community in the United States. Belvedere and Tiburon share a post office and the 94920 ZIP code.