The earliest archaeological evidence of human habitation of the territory of the city of San Francisco dates to 3000 BC. The Yelamu group of the Ohlone people resided in a few small villages when an overland Spanish exploration party, led by Don Gaspar de Portolá, arrived on November 2, 1769, the first documented European visit to San Francisco Bay. The first maritime presence occurred on August 5, 1775, when San Carlos—commanded by Juan Manuel de Ayala—became the first ship to anchor in the bay. The following year, on March 28, 1776, the Spanish established the Presidio of San Francisco, followed by a mission, Mission San Francisco de Asís (Mission Dolores), established by the Spanish explorer Juan Bautista de Anza.

The historic center of San Francisco is the northeast quadrant of the city anchored by Market Street and the waterfront. It is here that the Financial District is centered, with Union Square, the principal shopping and hotel district, and the Tenderloin nearby. Cable cars carry riders up steep inclines to the summit of Nob Hill, once the home of the city’s business tycoons, and down to the waterfront tourist attractions of Fisherman’s Wharf, and Pier 39, where many restaurants feature Dungeness crab from a still-active fishing industry. Also in this quadrant are Russian Hill, a residential neighborhood with the famously crooked Lombard Street; North Beach, the city’s Little Italy and the former center of the Beat Generation; and Telegraph Hill, which features Coit Tower. Abutting Russian Hill and North Beach is San Francisco’s Chinatown, the oldest Chinatown in North America.

San Francisco is located on the West Coast of the United States at the north end of the San Francisco Peninsula and includes significant stretches of the Pacific Ocean and San Francisco Bay within its boundaries. Several picturesque islands—Alcatraz, Treasure Island and the adjacent Yerba Buena Island, and small portions of Alameda Island, Red Rock Island, and Angel Island—are part of the city. Also included are the uninhabited Farallon Islands, 27 miles (43 km) offshore in the Pacific Ocean. The mainland within the city limits roughly forms a “seven-by-seven-mile square”, a common local colloquialism referring to the city’s shape, though its total area, including water, is nearly 232 square miles (600 km2).