Shoshone County is the location of the Silver Valley, which is one of the richest sources of silver in the United States. It was also the site of tension between miners and mining companies in the late 1890s, which resulted in several strikes and military intervention. The conflict eventually culminated in the assassination of former Idaho Governor Frank Steunenberg in 1905. In 1972 the Sunshine Mine, located in Shoshone County, was the site of the worst mining disaster in U.S. history when 91 miners died from smoke inhalation when the mine caught on fire.