Union City is located in the southeast of the San Francisco Bay Area in Alameda County, California, the US. The city covers an area of 49.9 square kilometers and has a population of around 73,402. As a satellite city of Silicon Valley, it mainly serves to decentralize the population and as a residential area. The majority of the population is concentrated in the east and west of the city. 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.