Sa Dec used to be the capital of Dong Thap province, formerly inhabited
by the ancient Phu Nam Kingdom and later the Chan Lap (Tchen La)
In the 1700s, the area was exchanged with the Vietnamese for military aid. Since then many Vietnamese have settled in this area and effectively annexed this whole area. The Chan Lap were subsequently wiped out and assimilated by the Vietnamese and today the population consists mostly people of Chinese, Khmer, Cham and Thai origin.
Sa Dec has become less and less prosperous ever since Cao Lanh was named capital of the province to reward communist cadres from the area after the war ended. New constructions and developments are now occuring in Cao Lanh, the commercial hub of the region.