In Tran times, Con Son belonged to Chi Ngai commune, Phuong Son district (Phuong Nhan), Lang Giang, Kinh Bac. In the early 18th century, it belonged to Chi Linh district, Hai Duong town. After the August Revolution, it belonged to Cong Hoa commune, Chi Linh district.
Con Son has two festivals a year.
Spring festival originated from the commemoration of the death of Huyen Quang -Truc Lam de tam to (22/1). Autumn festival originated from the commemoration of the death of Nguyen Trai (16/8). Spring festival began after the death of Huyen Quang (1334), autumn festival came into being in 1962 and became a big festival since 1980 when Nguyen Trai was honoured to be the world cultural celebrity.
The scale of festival in Tran dynasty was not obvious, from Le dynasty to 1945, spring festival was not large but had an important role in Vietnam Buddhism, therefore, it was acknowledged by History of the unification of Great Vietnam. It was not only a festival of Buddhists but also a chance of enjoying spring for the youth. The festival began on the fifteenth of January and ended on 22 January. Today the festival lasts for the whole month of January but the important day is still on the eighteenth. The festival is purely religious. Great-grandmother comes here to recite the Buddhist scriptures, the youth climb the mountain to enjoy spring. In the evening, there are folk performances. Spring festivals though take place in the pagoda but visitors are mostly the youth, therefore, it can be said that Con Son spring festival is the festival of the youth. Every year, there are tens of thousands of visitors, however, the number of visitors coming to Kiep Bac is very small, equal to one fifth of Con Son visitors.
Autumn festival takes place at the same time with Kiep Bac festival, this is a double festival, Con Son-Kiep Bac festival, the two relics are only 6km away from each other and the travel between them is very convenient. Two third of visitors coming to Kiep Bac will visit Con Son and visitors coming to Con Son autumn festival will come to Kiep Bac. Con Son visitors are equal to two third of Kiep Bac visitors. Con Son autumn festival takes place during August, important day is the eighteenth although Nguyen Trai's death anniversary is in the sixteenth.