There's a Mountain of Pure Copper Under the U.P. — and America's First Mining Rush Happened There

Long before the California Gold Rush, there was the Michigan Copper Rush. In the 1840s, prospectors flooded into the Keweenaw Peninsula — that finger of land poking into Lake Superior — chasing something remarkable: native copper, meaning copper so pure you could practically hammer it straight into shape without smelting it. That’s genuinely rare in the world.

The rush that followed predated the California gold rush by about six years and made the Keweenaw the center of American copper production for decades. As the National Park Service notes, “By 1849, this area provided 96% of the entire United States copper production; from 1845 to 1887 it was the largest copper producing region in the United States.” The copper from here helped wire and plumb a rapidly industrializing nation. At its height the Calumet & Hecla company, led for years by Swiss-born Alexander Agassiz, “produced one-half of the country’s copper” and made its Boston investors fabulously wealthy.

But here’s the truly mind-bending part: people were mining copper here long before any of that. Indigenous peoples worked the Keweenaw’s copper for thousands of years — by some estimates more than 7,000 years ago — making it one of the oldest known metalworking traditions on Earth. The last native copper mine finally closed in 1968.