Montaigle Castle (French: Château de Montaigle) is a ruined medieval castle in Falaën in the municipality of Onhaye, province of Namur, Wallonia.

It stands on a rocky spur overlooking the valleys of the Molignée and of the Flavion.

Following the official web-site of Onhaye, The Belgian government commissioned in 1867 the geologist Édouard Dupont to study the caves (locally called trous, lit., "holes") located in the rocky spur of Montaigle.

The "Montaiglian" layer was later renamed "Aurignacian", after the cave of Aurignac in the Pyrénées.

[1] This opinion is also indirectly in a book of Marcel Otte[2] Hawthorne Harris Wilder wrote yet in 1924 Montaiglian (or Augniracian) [3]