The Upper Mississippi Valley district ran on galena, lead sulphide in bright cubes that split into perfect steps, and the diggings around Mineral Point are where Wisconsin started. By 1829 this district was producing more than half the lead in the United States, worked by men who burrowed into the hillsides and slept in the holes, which is how the state got the badger. Pendarvis preserves the Cornish stone cottages they built. Old workings are on PRIVATE land and are genuinely dangerous; the historic site and local shops are the honest way in.
Galena, sphalerite, calcite
See it on the map
https://en.wikipedia.org/w/index.php?search=Upper%20Mississippi%20Valley%20lead-zinc%20district
Other places on the map within a couple of hours.