Jeongamsa Temple is a small rural temple situated halfway up Oseosan Mountain. There are few existing records that mention the temple’s beginning. Some suggest that it was built around AD 527 during the 5th year of Baekje King Seongwang’s reign, but there is little evidence to support this theory. The only reference alluding to a specific time is Yeojidoseo ("Detailed Survey of Korean Geography" published during the late Joseon dynasty). It states Jeongamsa Temple's location as on Oseosan Mountain, and Oseosan Mountain being surrounded by Hongsan Mountain and Baegwolsan Mountain and intersected by Hongju, Gyeolseong, and Boryeong. This indicates the temple was recognized in the mid-18th century and around the same time, Garamgo (a book about temples, published in the late 18th century) also states that Jeongamsa Temple is located approximately 11 kilometers to the east of Gyeolseonghyeon. It is still uncertain whether the temple referred to is Jeongamsa Temple on Oseosan Mountain.
Some foundation stones within the temple site measure 70-80 centimeters on each side. These stones indicate that the old Buddhist shrine of Jeongamsa Temple was laid out with five kan (Korean unit of measurement indicating the space between two pilars) at the front and three kan on the side. Future archaeological studies will help identify the true history of Jeongamsa Temple.