The papers are largely Lady Cromer's, but include 400 letters to her from Lord Cromer, 1901-16, 28 letters from him to Gertrude Bell, 1908-14, and a small quantity of other letters from and to him, as well as a substantial amount of her correspondence. There are papers relating to educational and medical work in Egypt, where Lord Cromer was British Agent and Consul-General 1883-1907, and the photographs in the collection include some 200 of Egyptian scenes.
Family papers include letters to Lady Cromer from her brother, Lord Alexander Thynne (killed in action 1918), and notes on Longleat and the pedigree of the Thynne family.