Tin Keo means foothill in Tay language, Tin Keo Hill is located at the foot of De pass, in Tin Keo hamlet, Phu Dinh commune, the center of An Toan Zone. On December 6, 1954, the decision to approve the battle plan for the spring of 1954 was made here along with the decision to open the Dien Bien Phu campaign. Tin Keo is currently one of the important relics in the system of historical relics of the resistance war of Dinh Hoa ATK.
Source: Collected internet.