William M. Nichols was president of the Yellowstone Park Company, the H.C. Child Corporation, the Spanish Creek Ranch, and other enterprises. Papers include general correspondence (1946-1957); financial records; minutes of the Yellowstone Park Company (1955-1962); and an extensive subject file (1914-1966) maintained both by Nichols and by his son John Q. Nichols, concerning the various corporate and financial affairs of the Nichols and Child families.