Fort Mason, in San Francisco, California is a former United States Army post located in the northern Marina District, alongside San Francisco Bay. Fort Mason served as an Army post for more than 100 years, initially as a coastal defense site and subsequently as a military port facility. During World War II, it was the principal port for the Pacific campaign. Fort Mason originated as a coastal defense site during the American Civil War. The nucleus of the property was owned by John C. Frémont and disputes over compensation by the United States continued into 1968.