Arpa river begins at an altitude of 3200 m and has its origins in the northwest of Artsakh. The total length is 126 km (in Armenia, 90 km).
The upper river is a rapid mountain stream that flows through the gorge and has a great fall. Then the river flows near the famous waterfall of Jermuk and takes a water source.
The gorge of the river Arpa unusually picturesque, it passes through the highway leading from Yerevan, Artsakh and Iran. The area is also famous for its caves, where as a result of excavations by archaeologists had found the remains of a unique people and objects end of V millennium beginning of IV millennium BC. e.