Nagorno-Karabakh is a de facto independent republic in the South Caucasus , officially part of the Republic of Azerbaijan , about 270 kilometres (170 miles) west of the Azerbaijani capital of Baku , and very close to the border with Armenia.
The Soviet Union incorporated the predominantly Armenian region as the Nagorno-Karabakh Autonomous Oblast ( NKAO ) in the Azerbaijan SSR in 1923 . On December 10 , 1991 , as the Soviet Union was collapsing , a referendum held in the NKAO and the neighboring district of Shahumian resulted in a declaration of independence from Azerbaijan as the Nagorno-Karabakh Republic ( NKR ), which remains unrecognized by any international organization or country , including Armenia.
In the final years before the dissolution of the Soviet Union, the region became a source of dispute between Armenia and Azerbaijan, culminating in the Nagorno-Karabakh War . Since the end of the war in 1994 , most of Nagorno-Karabakh and several regions of Azerbaijan around it remain under Armenian military control. Since then, the parties have been holding peace talks mediated by the OSCE Minsk Group
Source: Nagorno-Karabakh, Wikipedia