The Kafue River is the longest river lying wholly within Zambia at about 1,600 kilometres (990 mi) long. It is the third largest tributary of the Zambezi (after the Luangwa and Shire), and of Zambia's principal rivers, it is the most central and the most urban. More than 50% of Zambia's population live in the Kafue River Basin and of these around 65% are urban.