Keweenaw Peninsula

The cities of Houghton, the peninsula's largest population center, and Hancock, are located along the shores of the Keweenaw Waterway.

The ancient lava flows of the Keweenaw Peninsula were produced during the Mesoproterozoic Era as a part of the Midcontinent Rift between 1.096 and 1.087 billion years ago.

[1] This volcanic activity produced the only strata on Earth where large-scale economically recoverable 97 percent pure native copper is found.

[2] The Keweenaw Peninsula and Isle Royale, formed by the Midcontinent Rift System, are the only sites in the United States with evidence of prehistoric aboriginal mining of copper.

The northern end of the peninsula is sometimes referred to as Copper Island (or "Kuparisaari" by Finnish immigrants), although this term is becoming less common.

Lake Superior significantly controls the climate of the Keweenaw Peninsula, keeping winters milder than those in surrounding areas.

Official records are maintained close to the base of the peninsula in Hancock, Michigan,[9] where the annual snowfall average is about 220 in (560 cm).

Beginning as early as seven thousand years ago and apparently peaking around 3000 B.C., Native Americans dug copper from the southern shore of Lake Superior.

The focus of copper working seems to have gradually shifted from functional tools to ornamental objects by the Late Archaic Stage c. 1200 B.C.

[15] The Keweenaw's rich deposits of copper (and some silver) were extracted on an industrial scale beginning around the middle of the 19th century.

Hard rock mining in the region ceased in 1967 though copper sulfide deposits continued for some time after in Ontonagon.