Gameunsaji Temple Site was built by King Munmu (AD 661-681), the king of Silla who unified Baekje and Goguryeo in the late 7th century. The purpose of the temple site was to pray for help and guidance from Buddha against Japanese invasion. Unfortunately, King Munmu passed away before the completion of the temple, and left a will to be cremated and buried in the East Sea so that he may reincarnate as a sea dragon in order to protect the country. As he wished, King Munmu's ashes were scattered at Daewangam of the East Sea. The temple was completed and was named by his son, King Sinmun (AD 681-692) in respect and appreciation for his father.
Gameunsaji Temple Site was rebuilt in 1979 based on the discovery of the site's foundation after two years of archeological research. The three-story stone pagoda at the temple site is a reminent of the early period of unified Silla, assembled with several parts which rise up to 13.4m high, known to be Silla's highest three-story pagoda.