Nagorno-Karabakh is a de facto independent but unrecognized state within Azerbaijan. It covers 4,400 sq km (1,700 sq mi) and has a population of 140,000 people (2012 estimate). The country is in the shape of a kidney bean. Apart from Azerbaijan, the nearest foreign country is Armenia, across the Lachin corridor, about 4 km away.
Nagorno-Karabakh is a landlocked country. It officially known as the Nagorno-Karabakh Republic, was formed as the successor to the Nagorno-Karabakh Autonomous Oblast within the Azerbaijan SSR, under the Soviet Union. It came under the independent Azerbaijan after the collapse of the Soviet Union, but Azerbaijan has not ruled it since 1991.
Nagorno-Karabath is officially part of Azerbaijan, but is under Armenian control. Therefore it can only be entered via Armenia. This situation came about because when the Soviet Union collapsed, a referendum taken showed that the majority of the people in the Nagorno-Karabakh Autonomous Oblast wanted independence from Azerbaijan, and the setting up of the Nagorno-Karabakh Republic. Although the republic exists today, it is not internationally recognized.
Since 1994, the Nagorno-Karabakh region as well as some parts of Azerbaijan are under the joint military control of Armenia and Nagorno-Karabakh. Peace talks have been going on since then, mediated by the OSCE Minsk Group trying to find a peaceful resolution to the conflict.
Planning your visit to Nagorno-Karabakh, Country
There's only one way to Nagorno-Karabakh, and that's via Armenia. This is considered illegal entry into Azerbaijani territory by Azerbaijani authorities. If your passport shows a visa or stamp in Nagorno-Karabakh, stay away from going into Azerbaijan itself. Nagorno-Karabakh is considered a separatist entity. You risk arrest in entering Azerbaijan with evidence of having visited Nagorno-Karabakh.