Ban Phu Citadel, also known as Tam Van or Sam Mun, was built in the 15th century in Dien Bien Phu City, Dien Bien province. It covered an area of dozen of hectares. In front of the citadel were deep ditch, and two systems of defense works, which were three kilometers long and approximately two meters high. The foot of the citadel was covered with clusters of bamboo. The present- day Noong Het Commune was the center part of the citadel.
At present, a part of the wall of Ban Phu Citadel is restored so that visitors can picture the citadel is restored so that visitors can picture the citadel of the past. In the 18th century, Chinese invaders occupied the citadel. Hoang Cong Chat (1739-1769) was sent to fight against the invaders. After he died in 1769, Dien Bien residents erected a temple to commemorate in the area of the citadel, 12km from the center of Dien Bien Phu City. Ban Phu Citadel and Hoang Cong Chat Temple is an attractive tourist site in Dien Bien.