 The two main Native American tribal groups which dominated Minnesota at the time the lands were acquired by the United States were the more established Dakota Sioux , and the Ojibwe who had migrated into the area more recently . The two groups fought bitter territorial wars during the 18th century . In the mid @-@ 18th century the Battle of <unk> , in which the Ojibwe defeated the Sioux , permanently established northeastern Minnesota , particularly <unk> <unk> Lake , as Ojibwe territory <unk> the Sioux to southern and western Minnesota . Skirmishes between the groups continued in the 19th century including a battle near Lac <unk> in 1818 , a battle near Stillwater in 1839 ( the site became known as " Battle Hollow " ) , and another on the Yellow Medicine River in 1854 . 
