Fremont/frimnt/ is a city in Alameda County, California. It was incorporated on January 23, 1956, from the merger of five smaller communities: Centerville, Niles, Irvington, Mission San Jose, and Warm Springs. The city is named after American explorer John Charles Frmont, "the Great Pathfinder." Located in the southeast section of the San Francisco Bay Area in the East Bay region primarily, Fremont had a population of around 220,000. It is the fourth most populous city in the San Francisco Bay Area, and the largest suburb in the metropolis. It is the closest East Bay city to Silicon Valley, and is thus sometimes associated with it. The area consisting of Fremont, Newark (an enclave of Fremont), and Union City (formed from the communities of Alvarado and DeCoto), is now known as the Tri-City Area.