Barring the south, the Wasgamuwa National Park is almost entirely encompassed by rivers. The eastern boundary is defined by the famous long flowing Mahaweli Ganga, while the northern and western sides are bordered by the Amban Ganga and Dunuwila Oya respectively. The ancient tanks stand as evidence to the historical importance of the Wasgamuwa National Park and the religious sites are part of the story of Yudanganapitiya – the site where Sri Lanka's famous kings, Dutugemunu and Elara, camped during their mighty battles, in the 2ndCentury BC. The Wasgamuwa National Park has a history of being the place to observe the Sri Lankan Sloth Bear (a recognized subspecies of the Sloth Bear). The name Wasgamuwa is derived from the Sinhalese 'walas gamuwa' where walaha is bear and gamuwa means 'the woods'. Due to the decline in population of the Sri Lankan Sloth Bear, the most commonly seen animal on safari today is the Sri Lankan Elephant.