The 1868 Hayward earthquake occurred in the San Francisco Bay Area, California, United States on October 21. With an estimated Richter magnitude of 6.8–7.0 and a maximum Mercalli intensity of IX (Violent), it was the most recent large earthquake to occur on the Hayward Fault Zone. It caused significant damage and a number of deaths throughout the region, and was known as the "Great San Francisco earthquake" prior to the 1906 San Francisco earthquake and fire.