Thomas Conrad was a pioneer Montana merchant. This collection (1857-1899) consists of biographical and genealogical materials; outgoing correspondence to his wife Mary Ivory Conrad; legal documents; limited financial records; and memorabilia. Also included is a subgroup of incoming correspondence to Mrs. Conrad from her brothers during the Civil War. Much of collection documents pioneer life and conditions in Virginia City, Montana Territory.

Martha Plassmann (1850-1936) was a Montana pioneer, historian, and journalist. Collection consists of her autobiography and over 500 historical articles written for the Great Falls Tribune and the Montana News Association during the 1920s and 1930s. The articles, based on her own memories and on research, cover a wide range of topics, especially fur trappers, explorers, and vigilantes.

Wilbur Fisk Sanders (1834-1905) was a Bannack, Virginia City, and Helena, Montana, attorney, vigilante, and Republican politician. Collection (1856-1930) includes biographical materials; correspondence (1861-1905); diaries (1866-1867); legal documents; financial records; speeches; historical writings; and miscellany, including scrapbooks. There is a small subgroup of Harriet Peck Fenn Sanders' correspondence (1874-1902) and diaries (1888, undated).

William Wheeler (1824-1894) served as U.S. Marshal and as Montana Historical Society Librarian in Helena, Montana. Papers consist of outgoing correspondence (1859-1860, 1869-1871), including discussion of problems of Montana Territorial law enforcement; and biographical writings on Montana pioneers. [Portions same as MF 12].