The article dwells upon the history of the discovery of the Tumnin mineral spring, the establishment and development of the Far Eastern health resort «Goryachy Klyuch,» located in the basin of Chope creek, a tributary of the largest river in the eastern macroslope of Sikhote Alin, Tumnin river, located 25 km from the Strait of Tartary. A historical sketch since the first mentioning of the Tumnin mineral spring from 1903 to the present day, as well as the results of hydrogeological expeditions to determine the chemical composition and α-activity of Tumnin mineral water at different periods, are presented. A contribution of a geological expedition that established a large deep-lying tectonic structure permeable to upwelling thermal water flows is described. The role of the staff of the physiotherapy and balneology department of the Khabarovsk Medical Institute in the study of the mechanism of action and clinical effectiveness of the Tumnin mineral water is addressed. A balneological characteristic of nitric and siliceous thermal water, the basic therapeutic factor of «Goryachy Klyuch» health resort, which has always been popular among the Far East residents, but gained special importance and appreciation of patients during the pandemic of new coronavirus infection, is given. Currently, in the health resort «Goryachy Klyuch», patients with skin diseases, musculoskeletal, gynecologic, neurologic diseases, digestive tract disorders, metabolic conditions, upper airways, cardiovascular disorders, occupational diseases are treated using balneotherapy and other methods of non-drug therapy. At present, the health resort «Goryachy Klyuch» is going through a difficult but interesting period of improvement of recreation opportunities for the Far East residents.