Askeran Fortress, 18th-century fortress in Khojaly District, Azerbaijan.

Askeran Fortress is an 18th-century fortification on both banks of the Qarqarçay, about 24 km from Shusha. Its walls are 2 m thick and 9 m high, built of river stone and broken limestone with lime mortar. Round two-storey towers linked by narrow corridors served as observation posts; the right-bank section has double walls, the left-bank six towers.

Built in the 18th century on the orders of Panah Ali Khan, the fortress guarded the eastern gate of the Karabakh Khanate, comparable to the Derbent wall in Shirvan. Sources differ on the date and patron: some name Panah Ali Khan's son Mehrali Khan and the years 1758–1760, others Ibrahim Khalil Khan and 1783–1784. In June 1805 a Persian army of over 40,000 crossed here on its way to Shusha, and in March 1920 the fortress was taken during the Askeran battle.

The name Askeran comes from the Azerbaijani words əski (old) and Aran, meaning old Aran. The fortress was called the eastern gate of the Karabakh Khanate, comparable to the Derbent wall at Shirvan's northern gate. Its two sections on opposite banks of the Qarqar River are linked by the terrain and by the narrow passage the walls leave along the water.

The site sits in hilly terrain and is reachable from several nearby cities. Visitors should wear sturdy shoes, as the ground is uneven and partly steep in places.

The fortress was built directly into the natural hillside landscape, with the valley sides themselves serving as part of the defensive structure. This approach was economical and turned the terrain into a natural wall.