Azerbaijan–Iran border

During the 19th century the Caucasus region was contested between the declining Ottoman Empire, Persia and Russia, which was expanding southwards.

[2] By the Russo-Persian War (1804–1813) and the subsequent Treaty of Gulistan, Russia acquired the bulk of what is now Azerbaijan and parts of Armenia; a border was drawn which is the modern border between Iran and Azerbaijan (excluding the Nakhichevan section) and Iran and Armenia.

[2][5][4] During the First World War Russian Communists staged a successful revolution in 1917, whilst the peoples of the southern Caucasus had declared the Transcaucasian Democratic Federative Republic in 1918.

[6][7][8][9] In 1920 Russia's Red Army invaded Azerbaijan and Armenia, ending the independence of both, followed shortly thereafter by Georgia.

[10] An Iran–USSR border convention in 1954 made some minor adjustments along the frontier in the Mugan plain and near Deman and Namin, to Iran's benefit.