Armenia–Azerbaijan border
The Armenia–Azerbaijan border (Armenian: Հայաստան–Ադրբեջան սահման, romanized: Hayastan–Adrbejan sahman; Azerbaijani: Azərbaycan–Ermənistan sərhədi) is the international border between Armenia and Azerbaijan. Estimates of the border's length vary from 996 km (619 mi) to 1,007.1 km (625.8 mi). European routes E002 and E117 cross the border.
The de jure border follows that of the former Armenian Soviet Socialist Republic and the Azerbaijan Soviet Socialist Republic and consists of two main segments – that between Armenia and Azerbaijan's Nakhchivan exclave in the west, and the longer section between Armenia and 'mainland' Azerbaijan to the east. Additionally, there are a number of enclaves on either side of the boundary, however these no longer exist except in a de jure sense. The border between Armenia and Azerbaijan has been closed since 1991.