Fort du Trou-d'Enfer

The fortified complex stretches across forested grounds at 178 meters elevation, featuring stone architecture with a central courtyard and multiple defensive structures.

Built between 1878 and 1881 as part of Paris defenses, the fortress accommodated 800 soldiers and contained 40 artillery pieces within its reinforced walls.

The fortress grounds later served as a pheasant breeding facility for presidential hunting activities until the practice ended in 2010.

Access to Fort du Trou-d'Enfer requires advance arrangements through guided tours, with group visits priced at 400 euros per session.

The facility maintains two underground powder magazines capable of storing 200 tons of ammunition, connected by covered passages to the main barracks.

Location: Marly-le-Roi

Location: Bailly

Elevation above the sea: 178 m

Part of: Fortifications of Paris in the 19th and 20th centuries

Address: route de Maintenon 78160 Marly-le-Roi 78870

Phone: 0603060410

Website: https://memoire-et-fortifications.fr/fortifications/place-forte-de-paris/le-fort-du-trou-d-enfer-grande-guerre-paris

GPS coordinates: 48.84907,2.08656

Latest update: June 23, 2025 09:44