Passage: The South Nahanni River originates on the western slopes of Mount Christie of the Mackenzie Mountains, at an elevation of 1,600 metres (5,200 ft). It flows south on the Yukon – Northwest Territories border for 10 kilometres (6 mi), then turns south-east into the Northwest Territories at the Moose Ponds. It flows through the Selwyn Mountains, where it receives the waters of the Little Nahanni River, south of the Sapper Range.

Question: Where does the South Nahanni River originate from?
on the western slopes of Mount Christie of the Mackenzie Mountains