Sierra Leone sēĕr´ə lēō´nē, lēōn´; sēr´ə lēōn [key], officially Republic of Sierra Leone, republic (2005 est. pop. 6,018,000), 27,699 sq mi (71,740 sq km), W Africa. It is bordered by the Atlantic Ocean in the west, by Guinea in the north and east, and by Liberia in the south. Freetown is the