Along with Tonkin and Cochin China, Annam was the name given by the French to one of the three major regions of Vietnam. Annam was composed of nearly 57,000 square miles of land joining Cambodia and Laos on the west and the South China Sea on the east, north, and south of the seventeenth parallel. Its former capital was Hue; and other principal cities were Binh Dinh, Da Nang, Quang Tri, and Vinh. Anciently inhabited by the Cham people, Annam was conquered by the Chinese in the third century B.C. and remained a colony until the revolution of 986. The Chinese were expelled by invading Annamites, retook the area in 1407, and were expelled again in 1428, after which Annam remained an independent monarchy until 1802, when the French brought it under their control.

Annam was south of the Red River Delta and at several points was only 30 miles wide. Except for the Montagnards in the highlands, most of the people of Annam lived along the coast and, besides rice cultivation, engaged in a brisk coastal trade because of the abundance of sheltered bays along the coast.