The collection contains correspondence and other papers of Blanche Cavendish, as well as some papers of other individuals closely associated with her.
There is a series of correspondence, containing letters both sent and received by Blanche; this includes letters from Blanche to her sister and her children, personal letters from Margaret Newburgh, wife of Thomas Eyre, 7th Earl of Newburgh, and letters of condolence on the death of Blanche's eldest son, William Cavendish, who died in 1834 aged two. There are also items kept by Blanche Cavendish in memory of her son William, including poems, journal entries, locks of her son's hair and a painted portrait.
The collection also contains sketches attributed to Blanche Cavendish – a talented amateur artist – as well as her embroidered pin cushion. There is a small number of journals and notebooks thought to be by Blanche Cavendish, including a book of religious writing and a notebook dating from before her marriage with the title 'Fables written by the Duchess of Devonshire'.
There are also further papers thought to be by Blanche Cavendish, among them a list of ladies in waiting which details the number of waits they had in 1840; this includes the number of waits for Blanche Cavendish. There is also some sheet music composed by William Cavendish, Earl of Burlington, and the Countess of Carlisle, as well as samples of the Countess of Burlington's handwriting kept by her husband after her death.