Dong Dang Fortress is located on a hill near Dong Dang railway station and National Highway 4A, leading into Dong Dang Town (Cao Loc District, Lang Son Province). This site stands as a powerful symbol of the indomitable spirit and heroism of Vietnamese soldiers and civilians during the 1979 northern border defense, which took place 46 years ago (February 17, 1979 – February 17, 2025).
Built by the French colonialists in 1940, Dong Dang Fortress features a three-tiered structure, measuring 60 meters wide and 100 meters long. Its intricate design includes an upper level for observation, a middle level with rooms and gun ports for combat, and a lower level used to store military supplies, ammunition, meeting rooms, and food.
Dong Dang Fortress was an extremely robust military structure, featuring bunkers facing all four directions. Above ground, clusters of reinforced bunkers with gun ports protruded from the mountaintop.
During five days of fierce fighting, the enemy called for our troops to surrender, but our soldiers remained resolute. On February 22, 1979, the enemy detonated approximately 10 tons of explosives, collapsing the fortress’s entrance and causing the sacrifice of hundreds of soldiers and civilians.
Every year on February 17, families like those of Mr. Tran Van Nam and Tran Ngoc Son (residents of Hanoi) visit Dong Dang Fortress to pay respects to their older brother, Tran Van Hong, who sacrificed his life defending the fortress in 1972.
In less than half a month of combat at the beginning of 1979, about 19,000 Chinese troops were neutralized on the Lang Son front. Facing mounting losses, the enemy retreated back across the border.
To achieve this victory, the 3rd Sao Vang Division suffered nearly 1,500 casualties; the 337th Division lost 650 soldiers; and the 338th Division sacrificed 260 lives. Additionally, 20 individuals and 14 units were awarded the title of Hero of the People’s Armed Forces.
Forty-six years have passed since the fortress endured relentless bombardment during the 1979 border defense. Today, children play freely atop its grounds. From here, one can observe bustling trade between Vietnam and China along the border.
The past has closed, and now relations between the two countries are stronger than ever, fostering cooperation in areas ranging from economics to social development.
Exploring Inside Dong Dang Fortress, Lang Son
After the 1979 border defense, the top section of Dong Dang Fortress was destroyed, leaving only two entrances—east and west—intact out of the original four.
From Dong Dang Fortress, key transportation routes such as the Dong Dang-Hanoi railway line, National Highway 1A (Lang Son-Hanoi), National Highway 1B (Lang Son-Thai Nguyen), and National Highway 4B (Lang Son-Cao Bang) can be observed.
Large concrete slabs remain as traces of the devastating blast that occurred in 1979.
Mr. Luong Van Bo (52 years old, caretaker of Dong Dang Fortress) leads journalists on a tour to explore the underground tunnels deep within the mountain.
Most tunnel entrances were constructed in reinforced bunker styles with gun ports facing all directions. The deepest accessible point of the tunnels lies approximately 30-40 meters below ground.
Some tunnels are blocked by soil and rocks.
Inside the tunnels, there are ventilation systems and air holes. The tunnels are about 2 meters high and 1.5 meters wide, designed with arched ceilings.
According to Mr. Luong Van Bo, the command room once used by French colonists measures roughly 3 meters wide and 2 meters high.
Along the tunnels are gun ports intended for defense in case the enemy infiltrated the fortress.
Mr. Bo noted that these belts belonged to brave soldiers who sacrificed their lives and were found inside the tunnels.
Some bunkers still bear clear traces of bullets and artillery fire. Recently, Dong Dang Fortress was recognized as a National Historical Site by the Ministry of Culture, Sports, and Tourism.
