Onyang Onsen Grand Hotel
- Location
- Asan, South Chungcheong, South Korea, South Korea
- Water type
- sodium chloride, bicarbonate
- Temperature
- 43 °C
- pH
- 7.3
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
Onyang Hot Spring Historic is located in Onyang-eup within Asan City in South Chungcheong Province, South Korea, representing one of the most historically documented hot springs in Korean history — records indicate these bicarbonate thermal waters have been used for bathing for over 1,600 years, with Joseon Dynasty kings including Taejong, Sejong the Great, and Hyojong making official royal visits to 'take the waters' at Onyang, making this the most historically prestigious royal spa site on the entire Korean Peninsula. The bicarbonate mineral waters of Onyang's deep granitic springs are naturally warm, clear, and characterised by a high pH producing exceptionally soft bathing water, cherished within a tradition of Korean bathing practiced at this site continuously for over a millennium for the comfort it leaves on the skin and for general well-being. Onyang's Hyeonchungsa Shrine — dedicated to Admiral Yi Sun-sin, Korea's greatest naval hero who defeated the Japanese fleet with his ironclad 'turtle ships' during the Imjin War — stands just outside the city, making the royal hot spring and the national hero's memorial together the most history-saturated destination in South Chungcheong Province.