Tax papers (1904-1947), company correspondence (1909-1947), financial records including incoming statements and bank statements (1914-1929), financial papers for individual companies (1907-1953), mining bulletins (1926-1928), and over 200 maps and plans. The materials relate to the operations of the company and to the corporations in which it invested. Most of these companies were involved either in mining or in railroads.

Collection includes a variety of business records of the Knight Investment Company, including: articles of incorporation, state certificates, patents, abstracts, deeds, receipts, bonds, wills, certificates, affidavits, company reports, surveys, letters, oaths, shipment orders, pool agreements, proxy agreements, letters of administration, leases, blueprints, tax forms, and other legal documents. Items document the business of the company between 1883 and 1964.