Founding of the Sierra Club

Date: May 28, 1892 • Location: San Francisco, United States

In San Francisco, John Muir organizes the Sierra Club.

San Francisco, officially the City and County of San Francisco, is the 17th-largest city and second-densest major city in the United States, with a 2025 population of 826,079. It is the fourth-most populous city in California and the second most-populous in the Bay Area. Some 4.6 million residents live in the city's metropolitan statistical area. Around 9.2 million live in the San Jose–San Francisco–Oakland combined statistical area, the fifth-largest in the United States. San Francisco is a global center for technology and finance, and is well-known for its affluence, eclectic architecture, and mild climate.