Fremont (/ˈfriːmɒnt/) is a city in Alameda County, California, United States. Located in the East Bay region of the Bay Area, Fremont has a population of 230,504 as of 2020, making it the fourth most populous city in the Bay Area, behind San Jose, San Francisco, and Oakland. It is the closest East Bay city to the high-tech Silicon Valley network of businesses, and has a strong tech industry presence.

The city's origins lie in the community that arose around Mission San José, founded in 1797 by the Spanish under Padre Fermín Lasuén. Fremont was incorporated on January 23, 1956, when the former towns of Mission San José, Centerville, Niles, Irvington, and Warm Springs unified into one city. Fremont is named after John C. Frémont, a general who helped lead the American Conquest of California from Mexico and later served as Military Governor of California and then U.S. Senator.

The recorded history of the Fremont area began on June 6, 1797, when Mission San José was founded by the Spaniard Father Fermín de Lasuén. The Mission was established at the site of the Ohlone village of Oroysom. The tribe lived between present-day San Francisco and Monterey and more lands eastward. They lived in dome-shaped shelters made out of redwood bark or woven tule. They were primarily hunter-gatherers; men hunted and trapped waterfowl, rabbits, deer, elk, and bears, whilst women gathered nuts, berries, and root vegetables. The Ohlone tribe lived beside rivers and estuaries because of the natural resources like fish and shellfish. In warm weather, men wore mostly nothing; in the winter, they wore animal hide or feather capes. Other than the weather, ceremonies also decided what the Ohlone men wore. The women wore deerskin aprons over skirts made of tule or shredded bark.

Until 1769, the tribe lived peacefully but Spanish soldiers and missionaries arrived in California to expand Spanish dominion in the Americas and convert the Native Americans to Catholicism. The Ohlone people weren't intimidated by the Franciscan priests, who welcomed them into their missions to live and work. Before missions, the Natives used tools made of stone, animal bones, and wood. The missionaries taught them how to make metal tools and weapons and priests also showed them how to make adobe bricks. The bricks were then used to build missions rather than for the tribe to utilize. The Spaniards brought cattle, pigs and sheep and encouraged the Ohlone to give up hunting and gathering to try farming and ranching instead. Living in the missions meant Ohlone people were forced into converting to Christianity and told to forget the superstitious beliefs that connected them to nature. Along with that, overpopulation caused food shortages and the Spanish brought diseases to the tribe, causing a lot of deaths and trouble that made an impact on a lot of lives.

On their second day in the area, the Mission party killed a grizzly bear in Niles Canyon. The first English-speaking visitor to Fremont was the renowned trapper and explorer Jedediah Smith in 1827. The Mission prospered, eventually reaching a population of 1,887 inhabitants in 1831. The influence of the missionaries declined after 1834 when the Mexican government enacted secularization.

José de Jesus Vallejo, brother of Mariano Vallejo, was the grantee of the Rancho Arroyo de la Alameda Mexican land grant. His family was influential in the Fremont area in the late colonial era and owned and built a flour mill at the mouth of Niles Canyon. In 1846 the town's namesake John C. Frémont led a military expedition to map a trail through Mission Pass for reaching the Pacific coast and to take possession of California from Mexico for the United States.

The Fremont area grew rapidly at the time of the California Gold Rush. A town called Mission San José grew up around the old mission, with its own post office from 1850. Agriculture dominated the economy with grapes, nursery plants and olives as leading crops. In 1868 the 6.8-magnitude Hayward earthquake on the Hayward Fault collapsed buildings throughout the Fremont area, ruining Mission San José and its outbuildings. Until the 1906 San Francisco earthquake caused its destruction, the Fremont area's Palmdale Winery was the largest in California. The ruins of the Palmdale Winery are still visible near the Five Corners in Irvington at the intersection of Washington Boulevard and Osgood. From 1912 to 1915, the Niles section of the Fremont area was the earliest home of California's motion picture industry (see Essanay Studios). Charlie Chaplin filmed several movies in the Fremont area, most notably The Tramp.

Fremont was incorporated in 1956 under the leadership of Wally Pond, chair of the incorporation committee, when five towns in the area, Irvington, Centerville, Mission San José, Niles, and Warm Springs, came together to form a city. Glenmoor Gardens, the largest subdivision in Fremont, was under construction in the area, by developers Ralph E. Cotter Jr., James R. Meyer, civil engineer Fred T. Duvall, and contractors James L. Reeder, and Robert H. Reeder. When the Glenmoor Gardens Homeowners Association (GGHA) was incorporated, in March 1953, there were no more than 75 houses in the subdivision. It was probably the first such organization in the Fremont area; in its scope and structure. The five-member board of directors (which included James Meyer and James Reeder) was set up to oversee a full range of services, from police and fire protection to street maintenance (which later became the purview of the city government).