Moraga is a city located in Contra Costa County, California, the US. It became a city on November 13, 1974. Contra Costa County is located in the eastern San Francisco Bay Area, California. The city covers an area of 24.4 square kilometers and has a population of 16,016. On 2014 June 23rd, 11 district heads from Wuhan signed the Memorandum of Friendly Cooperation with 11 mayors from cities in the Silicon Valley area of USA.