The collection consists of falls into two series: Papers and Diaries. The Papers primarily reflect Brown's political concerns and activities in Montreal between 1832 and 1838. They include excerpts from the Vindicator newspaper, notes, resolutions, memoranda and speeches, as well as letters to Brown concerning Florida politics and the United States' negotiations with Native peoples, 1841-1843. There are also business documents and letters; essays by Brown on the 1837-1838 Lower Canada Rebellion and the annexation of Canada; and a journal kept during an ocean voyage in 1838.

The Diaries consist of seven notebooks written in pencil, or perhaps more properly dictated, by Brown in 1887-1888. They were transcribed by F. J. Nobbs in 1987.