Althorp Papers. Vol. md. Letters from his sister, Lady Sarah Spencer. For Spencer's letters to Sarah see Add. MSS 77720-77722 below; 1851, [1856?]-1910.
Althorp Papers. Vol. mdviii. Letters from: 1. His uncle, George Spencer, known as Father Ignatius, Superior of the Order of Passionists in London; 1858-1863. 2. His aunt Frances, Dowager Lady Clinton; 1851-1872, n.d.
Althorp Papers. Vol. mcmiii. 1. Letters from Gen. W. Cartwright of Flore House, Weedon, relating to the setting up of a Northamptonshire Club in Northampton and other local matters; 1858-1872. 2. Correspondence with Maj. George John Whyte-Melville of Wootton Hall, Northampton, writer and hunts...
Althorp Papers. Vols. mcmlxxvi-mcmlxxxiv. Incomplete indexes to correspondence in Add. MSS 76944-76967 above with Sir George Trevelyan; 1882-1894. Nine volumes.
Althorp Papers. Vol. mdcxxiii. Correspondence with W. E. Forster, Chief Secetary Ireland, (1880-1882); 1880-1885. William Edward Forster, MP: Correspondence with 5th Earl Spencer: 1880-1885.
Althorp Papers. Vol. mdcclxxxviii. Correspondence with Sir Henry Brackenbury, Assistant Under-Secretary, Police and Crime, Ireland; 1882-1885, 1896. General Sir Henry Brackenbury, GCB: Correspondence with 5th Earl Spencer: 1882-1896.
Althorp Papers. Vol. mdxviii. 1. Correspondence with Henrietta Lyttelton, wife of Spencer Lyttelton; 1868-1909, n.d. 2. Letters from William Henry Lyttelton, son of Spencer and Henrietta Lyttelton; 1867-1876. Hampton Court, Middlesex: Admissions to copyhold tenure: 1662-1708: Partly Lat.
Althorp Papers. Vol. mdxxvi. Correspondence with Lord Charles Bruce, husband of Charlotte Spencer's sister Augusta and librarian at Althorp; 1861-[1904?]. Thomas Coke, Vice-Chamberlain: Appointments as Deputy Lieutenant of Derbyshire: 1700-1715.