Frobisher's papers comprise a letterbook of the North-West Co. containing copies of letters written by Frobisher from April 1787 to October 1788, two original letters to Simon McTavish, 1796, and one from him, 1787, business and legal documents, largely concerning the estate of James McGill, 1810-1834, and a diary, 1806-1810, mostly a record of where he dined.

Collection contains a manuscript letter from Henry Lyman to his wife, Mary, in Granby; dated July 25, 1849, when the druggist shop Wm. Lyman & Co. was located at 194 and 196 St. Paul St. in Montreal, the letter deals principally with the cholera epidemic in the city.