The earliest evidence of humans in the San Francisco territory is dated at roughly 3000 B.C. The first habitants of the territory were the Yelamu group, of the Ohlone village, but they sparsely populated the territory. A spanish exploration expedition, headed by Don Gaspar de Portola came to the area in 1769, and is recognized as the first record of Europeans to come to San Francisco Bay. On March 28, 1776, the Presidio of San Francisco, of the Royal Fortress of San Francisco, was established as a military base by Juan Bautista de Anza.
When the area became independent from Spain in 1821, San Francisco was included as a part of Mexico, which lead to the privatizing of the land. The first independent homestead was constructed by William Richardson of England. Alongside the Mayor of Yerba Buena, Richardson laid out a city plan for roads, in order to expand the settlement into a larger town. The town was originally called Yerba Buena, and upon its expansion, American settlers who had traveled west began to call it home. During the Mexican-American War, California was claimed by John D. Sloat, and Yerba Buena was seized shortly after by American Captain John B. Montgomery. The territory was renamed San Francisco upon the ceding of the territory by Mexico to America.
Despite San Francisco becoming American land, it was not until later, during the California Gold Rush, that the area really started to grow in terms of population and as a town. In 1848 the influx of people brought the population from 1,000 to 25,000 by the end of 1849. When California was ultimately granted statehood, a military base, Fort Point, was erected at the Golden Gate, along with a fort on Alcatraz Island, in order to lock down the San Francisco Bay area.
Over time, San Francisco has faced many hardships, such as the San Francisco Plague of 1900-1904, and a major earthquake that hit San Francisco and widely affected California on April 18, 1906. This earthquake ravaged the city, causing buildings to crumble, fires to erupt and gas lines to burst. The damage of the earthquake destroyed over three-quarters of the city, and killed around 500 people. The rebuilding of the city posed quite a challenge, but those living in San Francisco were ready to rectify their city. The aftermath of the earthquake proved to be a time in which San Francisco strengthened itself, rebuilding to be bigger and better than ever.
Today, San Francisco is the largest hub of finance in Northern California, and is the only location that is a known as both a city and a county in all of California. San Francisco is the second-most densely populated city, compared with cities with a population of over 200,000, in the United States, falling second to NYC. That being said, it is the most densely populated city in California, as well as the fourth most overall populous city in the state. San Francisco is known for the Golden Gate Bridge, the former prison on Alcatraz and its temperate but enjoyable weather year round. San Francisco is a beautiful, welcoming city with something to offer everyone.