Settlers from Scandinavia, Germany, Ireland, Czechoslovakia and Russia, as well as elsewhere in Europe and from the eastern U.S. states increased from a trickle to a flood, especially after the completion of an eastern railway link to the territorial capital of Yankton in 1872, and the discovery of gold in the Black Hills in 1874 during a military expedition led by George A. Custer.
Bosættere fra Skandinavien, Tyskland, Irland, Rusland så vel som fra andre dele af Europa samt fra det østlige USA strømmede til, især efter færdiggørelsen af den østlige togforbindelse til hovedstaden Yankton i 1872 og fundet af guld i Black Hills i 1874 under en militær ekspedition, anført af George Armstrong Custer.