Fremont is a community in Alameda County, United States, California. This had been incorporated from the incorporation of Centerville, Niles, Irvington, Mission San Jos? and Warm Springs on January 23, 1956. The town is named after California's former US senator and military governor John C. Fr?mont, an American adventurer and former US senator. Fremont has a population of around 230,000 which is growing rapidly. It is one of the largest cities by land area and the fourth most populous city behind San Jose, San Francisco and Oakland in the San Francisco Bay Area. The city of Fremont and the towns of Newark and Union City is collectively known as the Tri-City Area.