 Their location of the northern boundary at a line drawn due east from the mouth of the Clearwater River, unknowingly placed the emerging mining settlement at Pierce outside of the county's boundaries while residents of the new Mormon settlement at Franklin were unknowingly within the established boundaries.Regardless of the geographic reality, the county seat was at Pierce.Growth at Pierce was so rapid that Shoshone County boasted the largest vote of any county within Washington Territory at the territorial election of July 8, 1861.