Situated at a three-way crossroads between Hai Duong, Quang Ninh and Haiphong, Yen Duc Site can be found outside the small village of Don Son, Yen Duc Commune, Dong Trieu District, Quang Ninh Provinces. This site has been a source of inspiration for poets of successive dynasties who have engraved their works on Cat Mountain.

There are five symbolic mountains in the rolling chain: Canh Mountain (symbolizing the art of ploughing fields); Dong Thoc Mountain (symbolizing prosperity); Thung Mountain (symbolizing rice mortar); Con Chuot (Mouse) Mountain (symbolizing the destruction of a paddy); and Con Meo (Cat) Mountain (symbolizing a cat lying in wait for a mouse).

On Thung Mountain, there is also a temple dedicated to the eight founding fathers of the hamlet and Canh Huong Pagoda devoted to Buddha. During the resistance against the French colonialists, the Canh Mountain held a cave where the Vietnamese army stored food, armaments and people. It also served as a shelter during air attacks. Yen Duc festivities take place annually on the 16th day of the first lunar month.