This new boundary alignment left the existing settlement at Pierce and the new settlement of Orofino as the county's only settlements. The county's population dwindled as prospectors abandoned Pierce for gold prospects at Elk City and Florence. Idaho Territory was created in 1863 and the first census of the territory in that year enumerated only 574 residents in Shoshone County. The county boundaries were expanded to include the Silver Valley by the legislative assembly of Idaho Territory when it officially created Shoshone County on February 4, 1864. The expanded territory contained no population at the second census of Idaho Territory in 1864. All of the county's 276 residents were located at Pierce and Orofino.