Fort de la Chartreuse, Military fort in Amercœur district, Liège, Belgium

Fort de la Chartreuse is a brick fort begun in 1817 on Mont Cornillon above Liège. Its entrance is a wide round arch edged with grey stone blocks, set in a massive red-brick wall streaked with damp; above it a stone plaque with a pointed cap sits among four small dark openings, and a shallow grey slab roof tops the wall. A lower rough stone wall stands to the right.

Dutch engineers built the fort between 1817 and 1823 on the grounds of a former Carthusian monastery as a defensive position for Liège. The Belgian military occupied it until 1988, after which nature gradually reclaimed parts of the site.

The fort takes its name from the Carthusian monastery that stood on Mont Cornillon from 1360 until the monks left in 1793. The hill had already been used for defence during the French bombardment of Liège in 1691. Since 1988 volunteers and nature groups have worked to restore the fort's galleries as a winter refuge for cave-dwelling species.

The fort sits on a hillside with marked pathways that guide visitors through the grounds and surroundings. Public transport connections are available near the entrance, making it relatively easy to reach on foot or by bus.

The 28th General Hospital, a US Army medical unit, occupied the fort from 26 September 1944 to 5 July 1945. A monument beside the entrance lists 48 prisoners shot and buried on the site during the German occupation. Since 2010 the upper floors have become unsafe to enter.