The Lake Vermilion-Soudan Underground Mine State Park is a Minnesota state park at the site of the Soudan Underground Mine, on the south shore of Lake Vermilion, in the Vermilion Range (Minnesota).

In the late 19th century, prospectors searching for gold in northern Minnesota discovered extremely rich veins of hematite at this site, often containing more than 65% iron.

[4] When the mine closed, level 27 was being developed at 2,341 feet (713.5 m) below the surface and the entire underground workings consisted of more than fifty miles of drifts, adits, and raises.

This technique was particularly suited to the Soudan Mine due to the strength of the hematite formations and the weakness of the encasing Greenstone.

This method was not possible in the nearby mines in Ely, Minnesota, because the iron formations there were fractured and thus were not as structurally stable as those at Soudan.

It has become a popular tourist site, often visited on the way to and from Ely and the Boundary Waters Canoe Area Wilderness.

[14] The University and the Minnesota Department of Natural Resources later expanded the laboratory to accommodate other physics projects, such as the MINOS neutrino detector, dark matter search experiments CDMS-II, SuperCDMS, and CoGeNT, as well as work on electroforming copper to create pure radiation-free copper.

Deep Underground Science and Engineering Laboratory, but that project was instead awarded to the Homestake Mine (South Dakota).