Original Croghan family manuscripts, 1769 -1819. One letter (1780) and a few other papers concern land claims of the elder George Croghan. William Croghan's papers include muster rolls and payrolls, 1776 1779, for his company in the Eighth Virginia Regiment, and similar records, 1779-1782, for the companies of John Bailey, Abraham Chaplin, Robert George, John Girault, and Richard McCarty in the Illinois Regiment; William's diary and notes on land surveys during a trip from Louisville to Nashville in 1784; a passport (1788) issued to him and signed by Estevan Mere, governor of Louisiana; and correspondence on land business, payment for military service, and administration of the Illinois grant. There are a few letters by his son John and a series of letters, 1811-1816, by his son George detailing his military experiences in Indiana and Ohio during the War of 1812, daring which he won acclaim as commander of Fort Stephenson for his brilliant defense against a larger force of British and Indians (1813).

In addition to the Croghans, writers of letters include John Bailey, John Brown, Jr. (Kentucky), Joseph Calvit, Arthur Campbell, John B. Campbell, Abraham Chapline, Daniel Clark, Jonathan Clark, Lardner Clark, Nicholas Clarke, Joseph H. Daviess, John Dodge, William Henry Harrison (1814), William Leas, Presley Nevill, John O'Connor, John C. Owings, Littleton Tazewell, and Robert Todd.