Location: The ATK (safety zone) lies in Phu Dinh Mountainous Area in Dinh Hoa District, Thai Nguyen Province.

Characteristics: It is significant to note that the site was head-quarter during the nine-year war against the French colonialism.

President Ho Chi Minh with leaders of the Party, the State and organs of the Central Party Committee and the Government worked here from 1947 to 1954. It is estimated that there are nearly 100 historical sites throughout Dinh Hoa’s mountains and forests. Of these, six sites are subject to national embellishment, namely:  – Tin Keo Site is located in Phu Dinh Commune where President Ho Chi Minh lived and worked in 1947-1948 and with the Politburo made decision on the Winter- Spring Campaign in 1953-1954. – Khuon Tat Hamlet belongs to Phu Dinh Commune where President Ho Chi Minh once lived and worked together with comrades Truong Chinh, Pham Van Dong, Vo Nguyen Giap and so on. – Phung Hien Historical Site is at Diem Mac Commune where comrade Truong Chinh worked. – Bao Lien Hamlet belongs to Bao Linh Commune where the Ministry of National Defence was based and General Vo Nguyen Giap worked between 1949 and 1954. – Quang Village is in Dinh Bien Commune where the ceremony to merge the Viet Nam Liberation Propagation Detachment and the National Salvation Detachment into Viet Nam Liberation Army was held on May 15, 1945.  – Former Cho Chu Prison in Dinh Hoa that was built by the French in 1916 to detain patriots and Vietnamese communists. Today, the historical site of Cho Chu Prison is preserved relatively intact and is open for visitors. Cho Chu Prison Relic is known as a place of historical and cultural interest in Thai Nguyen Province.

Also in this place on 19 May 2005, President Ho Chi Minh’s Memorial House was officially inaugurated for public service.

Visiting Dinh Hoa, visitors have a chance to sightsee the natural surroundings, such as Hang Pagoda, a seven-level waterfall, Bao Linh Lake, etc.