The fonds consists of a letter relating to Lord Dalhousie's visit to Perth in Upper Canada, and a newsclipping of an open letter to Lord Dalhousie regarding Wesleyan missionaries in Canada.
Letters to two unidentified persons. It appears that one at least is to James Gow, Windsor. In it McLachan tells of family matters, books he has read and the support spiritualism has given him through talks with his dead son, John.
Fonds consists of correspondence; photographs; and his long lost memoirs largely relating to his involvement in the 1837 Upper Canada Rebellion; and his interactions with such notables as William Lyon Mackenzie, Sir John A. Macdonald, Edward Barker, Pirate Bill and his daughter Kate, and a murderous Captain of the Fort Henry Guard.