 In 2011, the lake was named a National Natural Landmark by Secretary of the Interior Ken Salazar.The fragile shoreline of Hanging Lake is composed of travertine, created when dissolved limestone from the Mississippian Period Leadville Formation (through which Dead Horse Creek flows) is deposited on rocks and logs, creating travertine layers.Hanging Lake is located on a fault line and was formed when roughly an acre and a half of the valley floor sheared off from the fault and dropped to what is now the shallow bed of the lake.