Diaries, 1901-1968; papers and photograph albums relating to the Boer War and photography in military reconnaissance, including an unpublished manuscript, 1897-1902, service in Northern Nigeria on the Anglo-French Boundary Commission, 1902-1904, West Africa, 1903, West Indies, 1902 and Ordnance Survey of Scotland, 1904-1909; papers relating to the introduction and use of chemical warfare during World War One, 1914-1918, and on the North West Frontier, India, 1919-1920 andphotographs taken on the Western Front, 1914-1915 and 1919; articles written as Director of Irish Propaganda during the Anglo-Irish War, 1921; papers concerning appointments as Colonel Commandant and Representative Colonel Commandant, 1937-1944; papers concerning writing and publication of 'Gas!' The story of the Special Brigade (Blackwoods, 1934) and Commonsense and ARP (C Arthur Pearson, 1939) and draft chapters and photographs concerning the unpublished manuscript 'Adventures of an Engineer Subaltern' dealing with military career, 1897-1903; personal correspondence and papers relating to memorial service, 1900-1981; glass and film negatives covering career, 1897-1920.

Newspaper cuttings mostly from The Irish Times, Evening Herald and The Globe, 1899-1901, relating to the Second Boer War, South Africa, 1899-1902. Papers and photographs relating to the Mohmand Field Force, North West Frontier, India, May-Jun 1908, including pocket diary detailing operations of 1 Bn, Prince of Wales's Own (West Yorkshire Regt) against Mohmand tribesmen, 1908; typescript extract, written on 13 Aug 1908, from the Record of Service of 1 Bn, The Prince of Wales's Own (West Yorkshire Regt), Mohmand Expedition, May-Jun 1908; fifty nine mostly captioned photographs of the Mohmand Field Force, 1908, including the defences of H Company, 1 Bn, The Prince of Wales's Own (West Yorkshire Regt), Mutta camp, North West Frontier, India, 1908; two printed maps of the North West Frontier, India [1908]; printed booklet entitled Standing Orders for Mohmand Field Force, May 1908 by Maj Gen Sir James Willcocks (Victoria Press, Peshawar, India, 1908); cutting from The Sphere with printed map of 'Mohmand country', 9 May 1908. Five letters from Riall to his father and sister, and to Riall from his mother, 1906-1910, with letter to Riall from Sgt Lipscombe, 1 Bn, The Prince of Wales's Own (West Yorkshire Regt), relating to a Battalion shooting competition, 30 Mar 1910.