Château de Moha, Medieval castle ruin in Wanze, Belgium.

Château de Moha is a ruined stone castle on a sheer rock spur above the confluence of the Mehaigne and Fosseroule, about 100 m north of Moha village. Rough grey stone walls survive along the ridge, and a circular tower with a jagged top and a red-and-white flag stands at the highest point. A small wooden shelter with a pitched roof sits behind the left-hand wall.

The fortress was built in the 11th century to serve the Counts of Moha and the Prince-Bishops of Liège as a stronghold. In 1376, people from the city of Huy captured it, after which the site lost its military importance.

The name Moha probably comes from a Germanic term meaning "mossy gau", a reference to the damp ground at the Mehaigne and Fosseroule confluence. The castle is also called Sint-Gertrudiskasteel, after Saint Gertrude. The Walloon form of the village name is Mouha.

The ruin stands on a rocky spur about 100 m north of Moha village, above the confluence of the Mehaigne and the Fosseroule. The north side of the cliff holds climbing routes of about 18 m, mainly grades 4 and 5. The ruin has been under restoration since 1981, so parts of the masonry may be closed off.

The castle was first mentioned in 1031, built against invading Normans. Around 1890 the Belgian state bought the ruin and used it as a stone quarry for buildings in the area; restoration has been under way since 1981. On the rocks on the north side, about 18 m high, climbers find mainly grade 4 and 5 routes.