Lake Victoria is 68,800 square kilometres (26,560 mi�) in size, making it the continent's largest lake, the largest tropical lake in the world, and the second largest fresh water lake in the world in terms of surface area (third largest if one considers Lake Michigan-Huron as a single lake). Being relatively shallow for its size, with a maximum depth of 84 m (276 ft) and a mean depth of 40 m (131 ft), Lake Victoria ranks as the seventh largest freshwater lake by volume, containing 2,750 cubic kilometres (2.2 million acre-feet) of water. It is the source of the longest branch of the Nile River, the White Nile, and has a water catchment area of 184,000 square kilometres (71,040 mi�). It is a biological hotspot with great biodiversity. The lake lies within an elevated plateau in the western part of Africa's Great Rift Valley and is subject to territorial administration by Tanzania, Uganda and Kenya. The lake has a shoreline of 3,440 km (2138 miles), and has more than 3,000 islands, many of which are inhabited. These include the Ssese Islands in Uganda, a large group of islands in the northwest of the Lake that are becoming a popular destination for tourists.