Fort du Loch, Military fort in Guidel, France

Fort du Loch is a military fort in Guidel featuring an irregular pentagonal shape with rounded corners, surrounded by a wide moat and defensive walls. Two internal buildings within the complex once housed troops and stored military supplies.

The fort was constructed in 1756 to protect the port of Lorient from English attacks. It formed part of a broader defensive network along the Breton coast.

The fort's name comes from the nearby Loch stream, and the site is now a listed monument that walkers reach on foot from Guidel. Its low grassy mound and stone gateway are what remain visible of the defences built to guard the approaches to Lorient.

The fort is accessible via local roads in Guidel and allows visitors to explore the entire site including its outer walls and ditches. The best time to visit is during clear weather when you can fully walk the grounds.

Despite being built for war, the fort was never used in combat. Its wide moat, the wall pierced with loopholes (barbacanes) and the drawbridge controlling access survive as a complete example of a mid-18th-century coastal defence, listed as a monument historique on 1 June 1960.