The Monadnock Building is a historic 10-story, 204,625-square-foot (19,010.3 m2) office building at 685 Market Street in downtown San Francisco, California. The building was designed by the firm of Frederick H. Meyer and Smith, and completed in 1907, immediately following the 1906 San Francisco earthquake. The building stands immediately adjacent to both the BART Montgomery Street Station and the Palace Hotel, and across Market Street from Lotta's Fountain.