The David Hume Collection contains letters and other ephemera brought together from multiple acquisitions. The principal manuscripts are found in is the bound volume containing letters from David Hume to the Comtesse de Boufflers. There are also letters from Jean-Jacques Rousseau and others for a total of 59 letters. This collection of letters was the basis for the anonymously edited Private Correspondence of David Hume with Several Distinguished Persons, Between the Years 1761 and 1776. Now First Published From the Originals. (London: Printed for Henry Colburn and Co., 1820.) One of the McGill copies of this book belonged to the Montreal lawyer and book collector Frederick Griffin (1798-1877). In addition to this volume there are eight other Hume letters. Some of these have been published by Professor Klibansky and Ernest C. Mosser in New Letters of David Hume. (Oxford: Clarendon Press, 1954). Finally, there are photographic copies of Hume manuscripts held by the Royal Society of Edinburgh and typed copies of official letters on Canada from the manuscripts of Sir Mark Dalrymple.

Collection contains letters, memorial, other documents dealing with the cultivation of hemp in Lower Canada, including those of Jesse J. P. Pennoyer.

This material consists of the daily orders of the 148th Battalion during World War I.

These are letters from Selkirk to Miles MacDonnell, 1811-1813 and instructions concerning wages and contracts. Thirteen documents concern Lord Selkirk's conflict with the North West Company at the Red River Colony and Fort William.There is also a letter to Colonel Benjamin Walker, 1816.

2 albums of photographs by Notman, of the house, grounds, and stables at Ravenscrag.

Fonds contains "The journal of an English lady; or letters descriptive of the continent during the years 1829 and 1830" to which have been added water-colour illustrations by the author.

An Inuit grammar was compiled by Peck during his stay at Wakeham Bay in 1916.

The collection consists of typescripts and proofs of stories, essays and reviews.

Collection consists of Canadiana assembled by Charles Kadwell: Canadiana: or, A medley of sundry matters in print and manuscript, relating principally to the Canadas; (during the period of the rebel-lions;) the other British North American colonies; and the neighbouring United States; with views, maps, plans, portraits, &c. and private journals. 2 vol. Folio. Vol 1 includes "Remarks during a voyage from London to Montreal in the year 1832"; "Notes during a trip from Montreal to Upper Canada... 3rd-18th August 1838"; "Calendar of remarkable events relating to British North America and the United States". Mostly cuttings from newspapers. A pedigree of the Kadwell family has been inserted by L.G. Macdonald, Q.C., and annotated by Robert Howard. Vol. 2, mostly newspapers.

McLennan's manuscripts of his literary works include drafts of Old Canadian Songs, 1885, Eighteen Poems, 1885-1898, The Indiscretion of Grosse Boule, ca 1890, Une soeur, ca 1890, As Told to His Grace, 1891, Mon compère Melchior and an early version of A King for a Week, 1892, John McDonnell of Scotus, 1896; probably an early version of Spanish John, A Question of Courage, 1896?, The Span o' Life, 1897, translations of 8 poems from Henri Murger's La Vie de Bohème, 1885, the outline of a projected novel, The Losing Side, and his Notes pour servir à l'histoire de la ville de Montréal, 1880-1888.