According to temple legend, Meigetsu-in Temple began as a hut named 'Meigetsu-an' that was built in 1160 by Tsunetoshi SHUDO to pray for the soul of his father, Toshimichi, who died in the Heiji War and that this was later restored by Norikata UESUGI but the prevailing theory claims that he was the actual founding patron.
なお、寺伝では、平治の乱で没した首藤俊通（しゅどうとしみち）の菩提の為、永暦元年（1160年）、その子の経俊が「明月庵」を建立したのが草創とされ、上杉憲方は中興者とされているが、実際の開基は上杉憲方とみるのが通説である。