Armenia–Azerbaijan border

A Soviet enclave

Russia acquired Karabakh in 1813. In 1923 the Soviet government made Nagorno-Karabakh an Armenian-majority autonomous region inside Soviet Azerbaijan, cut off from Soviet Armenia by the Karabakh Range.^[3] Soviet border-drawing also left small villages of each republic as islands inside the other: Artsvashen, which Azerbaijanis call Bashkand, was Armenian land inside Azerbaijan, and Karki, which Armenians call Tigranashen, one of several Azerbaijani villages inside Armenia.^[2]

In 1988 Karabakh’s Armenians began demanding transfer to Armenia, which both Soviet Azerbaijan and Moscow opposed. When the two republics became independent in 1991, war broke out.^[3]

Two wars

By the early 1990s Karabakh Armenian forces, supported by Armenia, held Nagorno-Karabakh and much of southwestern Azerbaijan, including the land between it and Armenia. A ceasefire in 1994 was periodically broken but largely held.^[3] Each side took the exclaves surrounded by its own territory, and their people fled.^[2]

Fighting began again on 27 September 2020 and was the worst since the early 1990s. A Russian-brokered ceasefire on 9 November made Armenia give up military control of Nagorno-Karabakh, with Russian peacekeepers to guard the region and the Lachin Corridor left open to Armenia.^[3]

2023

The Lachin Corridor was blockaded from December 2022. In September 2023 an Azerbaijani offensive took full control of Nagorno-Karabakh, and by October more than 100,000 of its roughly 120,000 Armenians had fled.^[3] Rights groups say the blockade used food as a weapon of war; Azerbaijan says the operation restored order within its own borders and that Armenians could have stayed.^[4]

Drawing the line

In April 2024 the two countries moved to delineate their border formally, and Armenia agreed to hand over four abandoned Azerbaijani villages it had held since the first war.^[3] The exclaves are harder. Armenia’s main north–south highway runs through the Azerbaijani ones, and in 2022 Armenia proposed that each side keep what it now holds, while Azerbaijan said it wanted its exclaves back.^[2]

A peace text was agreed in March 2025, but Azerbaijan would not sign it until Armenia removed from its constitution what Azerbaijan sees as a claim to Karabakh.^[3] On 8 August 2025 President Ilham Aliyev and Prime Minister Nikol Pashinyan met Donald Trump at the White House, where they committed to respect each other’s territorial integrity and agreed a transport route across Armenia, with exclusive development rights for the US, called the Trump Route for International Peace and Prosperity.^[4] Its framework, published in January 2026, describes it as linking the main part of Azerbaijan with its Nakhchivan Autonomous Republic.^[1] In April 2026 the border commissions met in Armenia for the 13th time and exchanged draft rules for drawing the delimitation maps.^[5]