Sinjeongho is an artificial lake completed in 1927 as an agricultural reservoir, commonly known as Masan Reservoir. Mountains and the waterside harmonize well, and from 1993, a full-scale park development project created lawns and a sculpture park. Notably, the lawn serves as a cultural and artistic experience space for local residents. Various sports facilities, a 5km waterside circular walking trail, a lotus flower complex, an aquatic plant exhibition linked to the tail silkworm butterfly ecological learning site are provided. A local garden designed as a water garden using the natural terrain highlights beautiful scenery blending surrounding mountains and water. It adjoins Namsan Neighborhood Park and connects to Namsan hiking trails, allowing access to Sinjeong Lake Park along the trails. Many visitors come to enjoy cafes and food across the road and to appreciate the natural ecological environment and stroll the lake park.
Onyang Oncheon Land is a comprehensive hot spring water park located in downtown Asan (Onyang). Onyang Oncheon is the oldest hot spring in Korea, with a history recorded to be about 1,300 years, dating back to the Baekje and Unified Silla periods. During the Joseon Dynasty, it was a place where several kings, including King Sejong the Great, Sejo, Sukjong, Yeongjo, and Jeongjo, stayed for leisure or healing purposes. Onyang Oncheon Land offers hot spring baths (sauna), jjimjilbang (Korean sauna), a children's hot spring (kids water park), and a gym, allowing people of all ages to enjoy the Onyang hot spring water. The site supplies natural alkaline hot spring water (pH 8.42) throughout all facilities without any processing. Onyang Oncheon is a traditional hot spring renowned for its top-quality water in Korea, with various amenities making it an ideal place for rest and healing. Onyang Oncheon Land can be accessed via National Routes 21 and 45 through Oncheon-daero, Chungmu-ro, and Munhwa-ro; the closest highway interchange is Asan-Hyeonchungsa IC on the Asan-Cheonan Expressway. For public transportation, visitors can use the Janghang Line railway and the Seoul Metropolitan Subway Line 1 at Onyang Oncheon Station.
Onyang Oncheon is the oldest hot spring in Korea. According to historical records, it has a history of 1300 years, spanning the Baekje and Unified Silla periods. Sincheontang, located in this Onyang area, first opened in 1960. The hot spring water of Sincheontang is an alkaline simple spring with a temperature of 44~60℃ and a pH of 9.0. The source hot spring water of Sincheontang contains sodium bicarbonate and is a mildly alkaline and silica hot spring with various benefits such as muscle relaxation and improved blood circulation.
When King Yeongjo visited Onyang's Ongung Palace, Crown Prince Jangheon (Sado Seja), who accompanied him, practiced martial arts here. To commemorate this, the prince instructed Onyang county governor Yun Yeom to plant three zelkova trees. Later, in 1795, nineteen years after Yeongjo’s son Jeongjo ascended the throne, he ordered Onyang county governor Byeon Uijin and Chungcheong-do governor Lee Hyeongwon to construct a platform here. After the construction, a stele recording the process was erected beside the platform. The stele's front inscription, titled 'Yeonggodaebi,' was personally written by Jeongjo. In 1984, it was recognized for its value and designated as a Chungcheongnam-do cultural heritage resource.
The hot spring water of Onyang Tourist Hotel is a radium hot spring containing manitaon, supplied directly from the hot spring source at a high temperature of 57℃. It is a slightly alkaline hot spring water. The main components of the hot spring water are calcium, radium, magnesium, and other elements evenly contained. The primary benefits of the hot spring water include anti-aging for the skin, prevention of menopausal disorders, prevention and treatment of diabetes, cancer prevention and treatment, relief from fatigue and stress, treatment of gastrointestinal diseases, prevention and treatment of adult diseases, and benefits for neuralgia, rheumatism, eczema, skin diseases, cold sensitivity, and gynecological diseases.
Onyang Oncheon is the oldest recorded hot spring in Korea, with a history spanning about 1,300 years from the Baekje and Silla periods. It has been functioning as an actual hot spring bath for about 600 years. Notably, during the Joseon Dynasty, several kings including King Sejong, Sejo, Hyeonjong, Sukjong, Myeongjong, Yeongjo, and Jeongjo built royal palaces here and stayed for rest or treatment; records and relics of this remain today. The spring water has a high temperature of around 57℃. Its main component is radium-containing manitaon, featuring slightly alkaline quality and abundant quantity. It is known to be highly effective for neuralgia, arthritis, skin diseases, gastrointestinal diseases, hypertension, and various adult diseases as well as skin beautification. Besides excellent water quality, over 120 lodging facilities and hot spring baths are concentrated here, making it a major tourist attraction. The district also includes cultural properties such as 'Sinjeongbi,' built by Sejo to auspiciously mark the spring's emergence, and 'Yeonggodae,' built to commemorate Crown Prince Jangheon (Sado Seja) who practiced martial arts here.
