San Francisco, officially the City and County of San Francisco, is the fourth most populous city in California and the 12th most populous city in the United States, with a 2008 estimated population of 808,977. The only consolidated city-county in California, it encompasses a land area of 46.7 square miles (121 km2) on the northern end of the San Francisco Peninsula.

Today, San Francisco is a popular international tourist destination, renowned for its chilly summer fog, steep rolling hills, eclectic mix of Victorian and modern architecture and its famous landmarks, including the Golden Gate Bridge, cable cars, and Chinatown. The city is also a principal banking and finance center, and the home to more than 30 international financial institutions,[20] helping to make San Francisco eighteenth place in the world's top producing cities, ninth in the United States, and fifteenth place in the top twenty Global Financial Centers. San Francisco is unique in that a few of its parks and nearly all of its beaches within city limits form part of the regional Golden Gate National Recreation Area, which is one of the most visited units of the National Park system in the United States, with over 13 million visitors a year. It is also one of the largest urban parks in the world. The beaches and parks that form the Golden Gate National Recreation Area in San Francisco include Ocean Beach runs along the Pacific Ocean shoreline and is frequented by a vibrant surfing community; Baker Beach which is located in a cove west of the Golden Gate and part of the former military base, the Presidio. Within the Presidio is Crissy Field, a former airfield that was restored to its natural salt marsh ecosystem. The GGNRA also administers Fort Funston, Lands End, Fort Mason, and Alcatraz. The National Park Service also separately administers the San Francisco Maritime National Historical Park—a fleet of historic ships and waterfront property around Aquatic Park.