March 11, 1861
In the 1840s hundreds of people flocked to the Keweenaw Peninsula — a slender, rugged protrusion jutting sixty miles into Lake Superior. They came for copper. Eastern investors, speculators, adventurers and miners journeyed to the isolated region of the western Upper Peninsula in what became the nation’s first mineral rush. The copper rush led to the organization of Keweenaw County; Eagle River was chosen the county seat.
Source : Michigan is Amazing.