With the Cassiar gold rush in the 1870s, prospectors came into the area for the first time. Famously, the MacLeod brothers were found dead along the Nahanni in 1906 after reportedly staking a rich claim along the Flat River. Later two prospectors reached the South Nahanni from the Yukon by ascending the Ross River then crossing the divide to a source of the Nahanni and descended the river searching for the lost claim. One mysteriously died and was only found by his partner years later. During the following decades several more prospectors and trappers disappeared or were found dead along the Nahanni and its tributaries, starting rumors and giving the river a reputation of being extremely dangerous. This also gave rise to several of the names along the river including Deadman Valley and Headless Valley.