The King Le Temple is located in Den Village, Thuc Phan Ward, 11km from the provincial center. It is dedicated to King Le Thai To (also known as Le Loi Cao Hoang De). Legend says the temple houses the King's sword and royal robe. The King Le Temple is part of the Na Lu Citadel complex; this was a center of economic, cultural, and military activity for many ancient feudal dynasties. The Na Lu Citadel and King Le Temple are classified as national historical relics (Decision No. 837/QD-BVHTTDL dated March 3, 2009 and Decision No. 1568/QD-BT dated April 20, 1995).

The King Le Temple Festival is held annually on the 6th day of the first lunar month. The ceremonial part begins on the night of the 5th day of the first lunar month. The festival includes cultural and artistic activities and folk games such as raft racing, chess, stick pushing, tug-of-war, and grass pulling.