Back, Sir George, 1796-1878, British explorer in N Canada. He accompanied Sir John Franklin on arctic expeditions in 1818, 1819-22, and 1824-27. On an expedition (1833-35) to search for the missing John Ross, Back explored the Great Fish River (now Back River) and Montreal Island in the present Nunavut Territory. His Narrative of the Arctic Land Expedition appeared in 1836. On a later journey (1836-37) he explored the arctic coast of Canada.

Back, river, c.600 mi (970 km) long, rising in lakes, Northwest Territories, Canada, and flowing northeast through Nunavut across the tundra to Chantry Inlet. Numerous lakes lie along its course. It is named for Sir George Back, the first European to descend the river (1834).