The Grenfell papers comprise: correspondence, log books and other manuscripts and printed material, Grenfell's Commisions, honours and invitations, newspapers and newscuttings in English, Portuguese and Spanish mainly relating to Grenfell's career in the Brazilian navy and a folder containing genealogical material relating to the Granville and Grenfell families, especially John Granville Grenfell (1829-1866). The Grenfell papers include a manuscript account of the 'Cutting out of the Esmeralda', a bound volume containing the logs of four Brazilian naval vessels commanded by Grenfell, the Brig Marnham, the frigate Imperatrice, the Brig Cabocolo and the schooner Grecian and and a manuscript copy of the defence of Captain Grenfell on his court martial at Rio.

Correspondence in the collection include:

• Letter books in English and Portuguese dating from 1844-54, 1846-60 and 1851-52
• A large collection of letters from Thomas Cochrane 10th Earl of Dundonald the bulk of which date from 1843-62 relating to prize money owed to them both by the Chilean and Brazilian Governments with petitions to those governments.
• Letters from S S de Oliveira President of Rio Grande relative to operations in 1840.
• Letters from the Baron de Caxias relative to the operations in Rio Grande in 1843
• Correspondence with Rear Admiral Lainé Montevideo 1844-45
• Correspondence with British Authorities 1844-46
• Orders and letters relative to the voyage of His Imperial Majesty [Pedro II] to Rio Grande and S. Paulo, ca. 1846
• Letters and papers concerning the fire on the Ocean Monarch 1848
• Correspondence with French, British and U.S. authorities 1851-1852
• Letters from Manuel Moreira Castro, (friend and editor of Rio's Journal do Commercio)1851-1852.
• Letters from the Argentine (rebel) Governor J J Urquiza of Entre Rios 1851-54

[ Note: The Grenfell papers contains items written in Portuguese, Spanish and French, material written in a language other than English has been indicated in the list. ]