Đèo Văn Long was the French leader of the Autonomous Tai Federation of Northwestern Tonkin in post-war French Indochina. Under his father Deo Van Tri, he was the scion of a hereditary feudal noble line with roots in Yunnan province. He generated much revenue for the Federation by acting as a middleman in the opium traffic between the Tai Federation and the French. He compelled the Hmong of the Federation to sell to him at below-market prices, thus making enormous profit from his sales to the French. This made him rich, but severed his relationship with the Hmong of the Federation, who supported the Viet Minh during the First Indochina War. His use of force to suppress Hmong resistance also decreased his popularity with the Hmong. As the Dien Bien Phu campaign came to an end, he was helicoptered away to Hanoi. He later immigrated to France as a refugee, but died shortly thereafter. He was succeeded by Deo Nang Toi.