The Kionga Triangle was a small territory on the East Coast of Africa. It lay between the colonies of German East Africa, the major part of present-day Tanzania, and Portuguese East Africa, the present day Mozambique. The area covered just 1000 km² (400 mi²). It was German possession from 1894 to 1916, after which it became a possession of the Portuguese.
The Germans established an outpost south of the Rovuma River in 1894. Although there was no Portuguese presence in the immediate area, there had been a provisional agreement, in 1886, that the Rovuma river would mark the border between the two European national territories. There was an argument, therefore, that the German settlement had encroached onto Portuguese territory. The settlement of Kionga, now spelled Quionga, had a population of 4,000 inhabitants in 1910.
During the Great War, the Germans declared war on Portugal, in 1916. The Portuguese authorities seized the opportunity to 'restore' national sovereignty and promptly occupied the territory. At the end of the war, the Treaty of Versailles determined the border as running along the length of the Rovuma. This decision confirmed the Portuguese possession, but by German East Africa itself had fallen into British possession, as the Tanganyika Territory (TT). The local Makonde people thus learned to speak Portuguese, rather than German or English, to the administrative authorities. The Kionga Triangle was the only Portuguese territorial gain, de facto, for their participation in the First World War.
Since Mozambique became independent on 25 June 1975, the Kionga Triangle, or Quionga, has remained a part of Cabo Delgado Province.
- Thomas, H.B., "The Kionga Triangle", Tanganyika Notes and Records Volume 31 1951, pp. 47–50.