The Detroit and Lake Superior Copper Company Records contain correspondence, receipts, invoices, and reports of General Managers John R. Grout and James R. Cooper and Chief Clerk Z. W. Wright. It includes records from its predecessor, the Waterbury and Detroit Copper Company.

Note that the Keweenaw Historical Society filed the material into company files based on the content of the letter, not the correspondent.

Note that the records of the Detroit and Lake Superior Copper Company are split between this subseries and Series II of MS-020, Roy Drier Collection. Researchers are encouraged to consult both collections.