Fonds consists of records related to the life and activities of Rev. John A. O'Reilly, including correspondence regarding appointments; letters between Bishop Edward Patrick Roche and Rev. O'Reilly (1919); offers celebret for other dioceses (1919); correspondence concerning health (1921); and receipts for health care in Montreal (1922-1933). The fonds also includes his manuscript, "Rome: The Capital of the Christian World (1899) as well as newspaper clippings and printed material related to his life.