By the time of the American Civil War , many European immigrants were settling in the Midwest instead of the East : German Lutherans and Jews settled in Ohio , Wisconsin , Illinois , and eastern Missouri ; Swedes and Norwegians in Wisconsin , Minnesota and northern Iowa . By the time of the American Civil War , European immigrants bypassed the East Coast of the United States to settle directly in the interior : German immigrants to Ohio , Wisconsin , Minnesota , Illinois , and eastern Missouri ; Irish immigrants to port cities on the Great Lakes , especially Chicago ; Danes , Swedes , and Norwegians to Iowa , Wisconsin , Minnesota , and the Dakotas ; and Finns to Upper Michigan and northern\/central Minnesota .