Roc la Tour, Archaeological site in Monthermé, France.

Roc la Tour is a quartzite outcrop in the Château-Regnault state forest above Monthermé, reaching 408 metres and facing southwest. Its three tors rise seven to eight metres, with a small wall of ten to fifteen metres, and a large scree of stone blocks lies at the base. The rock is grey and brown, deeply fissured, with a broad slab overhanging a shadowed recess.

Excavations from 1980 to 1986 revealed human settlements dating back 15,000 years at this location. These discoveries established it as one of the oldest sites in the Ardennes with evidence of regular visitation in antiquity.

The name references an ancient stronghold that local legend connects to a lord's supernatural bargain. This tale remains part of how people understand and remember this place in the Ardennes.

The site sits at 400 meters elevation in the Château-Regnault state forest and is accessible via a hiking trail. A 7.6-kilometer route begins from Thilay church square and leads to this location.

The site's three quartzite tors, 7 to 8 metres high, are the supposed remains of the devil's castle, and the annual Ardennes Mega Trail endurance race traditionally passes through here. Climbers use 40 routes graded 3 to 6b on the rock.