 Father Louis Hennepin with companions Michel Aco and Antoine <unk> ( aka Picard Du Gay ) headed north from the area of Illinois after coming into that area with an exploration party headed by René @-@ Robert Cavelier , Sieur de La Salle . They were captured by a Dakota tribe in 1680 . While with the tribe , they came across and named the Falls of Saint Anthony . Soon , Du Lhut negotiated to have Hennepin 's party released from captivity . Hennepin returned to Europe and wrote a book , Description of Louisiana , published in 1683 , about his travels where many portions ( including the part about Saint Anthony Falls ) were strongly embellished . As an example , he described the falls as being a drop of fifty or sixty feet , when they were really only about sixteen feet . Pierre @-@ Charles Le Sueur explored the Minnesota River to the Blue Earth area around 1700 . He thought the blue earth was a source of copper , and he told stories about the possibility of mineral wealth , but there actually was no copper to be found . 
