Lord MacDonnell's papers consist of:
- General Correspondence and Personal Papers, 1859-1929, including letters to MacDonnell and his wife, newspaper cuttings, miscellaneous papers, speeches, personal papers, and photographs
- Papers about India, 1864-1930, including correspondence, printed official papers, papers about famine relief, miscellaneous papers, photographs, newspaper cuttings, and papers about the Indian Civil Service
- Papers about Ireland, 1893-1930, including papers about the foundation of Dublin University, papers about Irish Constitutional Reform, papers relating to the Irish Convention, miscellaneous Irish papers, and letters to Lady MacDonnell
- Additional papers, 1885-1955, including correspondence; papers relating to MacDonnell's last illness and death; and miscellaneous papers