The manuscripts consist of a small number of documents of the 13th to 17th centuries and an extensive collection of eighteenth century papers, including the private and official correspondence of the Howard family with most of the important men of the period. Among the public documents are papers and minutes relating to the "American War of Independence, the negotiations with the Americans in 1778-80 [and] the fifth Earl of Carlisle's mission to America as British commissioner". Of the private correspondence the largest group contains the letters of George Selwyn to the fifth Earl of Carlisle, 1767-1790.