The Dene, sometimes called Slavey, peoples have used the lands around Nahanni National Park Reserve for thousands of years. The first human occupation of the area is estimated to have occurred 9,000-10,000 years ago. Evidence of prehistoric human use has been found at Yohin Lake and a few other sites within the park. The local oral history contains many references to the Naha tribe, a mountain-dwelling people who used to raid settlements in the adjacent lowlands. These people are said to have rather quickly and mysteriously disappeared.