Union City is a city in the San Francisco Bay Area in Alameda County, California, United States approximately 30 miles from San Francisco and 20 miles north of San Jose. Incorporated on January 13, 1959, combining the communities of Alvarado, New Haven, and Decoto, the city has over 74,000 residents today and very diverse population. Alvarado is a California Historical Landmark (#503). The city celebrated its 50th Anniversary in 2009. The Cities of Fremont, Newark, and Union City make up the Tri-City Area, and to travel to other parts of city limts, you would have enter from nearby cities. The Tri-City Area hosts many local events, along with programs for the youth.