The papers cover most of McClintock's service career and in particular the Arctic voyages. There are official service documents; logs, 1831 to 1848, 1857 to 1859; diaries, 1848 to 1854, 1860 to 1862, 1879 to 1882; and a letterbook, 1865. The papers relating to the Franklin search expeditions include orders issued by Captain Horatio T. Austin, 1850 to 1851; a letterbook of Captain Henry Kellett, 1853; papers on the expedition led by Lieutenant Frederick G. Schwatka of the United States Army, 1878 to 1880; and several notebooks, including those kept during training courses, 1841 to 1842. Finally, there is private correspondence which includes letters received from Lady Jane Franklin and many other people involved in Arctic and maritime exploration; and letters written by McClintock to members of his family.

Administrative / biographical background
McClintock entered the Navy in 1831. He served as a midshipman in HMS SAMARANG, South America, 1831 to 1835, then in the survey ship HMS CARRON in the Irish Sea, 1835, and HMS HERCULES in the Channel, 1836 to 1837. From 1838 to 1841 he was in HMS CROCODILE on the North American Station. Between 1841 and 1842 he took courses in gunnery at HMS EXCELLENT and at the Royal Naval College, Portsmouth. McClintock next served as mate of HMS GORGON, on the South American Station, 1843 to 1845. He received his promotion to lieutenant in 1845 and was appointed to HMS FROLIC, Pacific Station, where he remained until 1847. For the next twelve years he was almost continually in the Arctic regions, serving on expeditions searching for Sir John Franklin and his men. During 1848 and 1849 McClintock was in HMS ENTERPRISE. From 1850 to 1851 he was lieutenant of HMS ASSISTANCE on the expedition led by Captain Horatio T. Austin. During the expedition of 1852 to 1854 he commanded HMS INTREPID, steam tender to HMS RESOLUTE, Captain Henry Kellett. On his return he was promoted to captain. Lady Franklin chose McClintock to command her private search expedition in the steam yacht FOX, from 1857 to 1859. This effort was at last successful in solving the mystery and many relics of the lost expedition and Franklin's final message were recovered from King William Island. McClintock was knighted on his return. He published an account of his expedition, 'The Voyage of the Fox in 1859'. In 1860 McClintock commanded HMS BULLDOG making soundings between Britain, Iceland, Greenland and Labrador, over the route of a proposed submarine telegraph cable. From 1861 to 1862 he commanded HMS DORIS in the Mediterranean, acting as escort to the Prince of Wales on his tour of the Near Fast, and from 1863 to 1865 commanded HMS AURORA in the Channel and the North Sea during the Prusso-Danish War and later in the West Indies. He was commodore-in-charge at Jamaica from 1865 to 1868, was promoted to rear-admiral in 1871 and from 1872 to 1879 was Admiral Superintendent of Portsmouth Dockyard, being appointed to vice-admiral in 1877. He sat on the organizing committee for the British Arctic Expedition of 1875 to 1876 led by Captain George S. Nares. From 1879 to 1883 he was Commander-in-Chief on the North American and West Indies Station. He was promoted to admiral and retired in 1884. See 'Life of Admiral Sir Leopold McClintock' by Sir Clements Markham, London, 1909.