Château de Commequiers, Medieval castle in Commequiers, France.

Château de Commequiers is a ruined castle beside a broad expanse of water in Commequiers, Vendée. It was built in the second half of the 15th and early 16th century in white Sallertaine stone as a mound ringed by an octagonal curtain wall articulated by round towers at the angles. The surviving walls are uneven, with gaps along the top edge; the tallest round tower keeps a few small rectangular openings and a flagpole, and a shorter broken tower stands beside it.

Louis de Beaumont, baron through his 1440 marriage to Jeanne Jousseaume, rebuilt the castle in white Sallertaine stone from the second half of the 15th century into the early 16th. In 1628, on Cardinal Richelieu's orders, it was dismantled like other regional castles, then passed to the Protestant de la Trémoille family. It was registered as a historical monument in 1926.

Each year the association Les Amis du Vieux Château de Commequiers holds "Médiévales", a two-day festival with participants in period costume. The castle, dismantled in 1628 on Richelieu's orders, passed to the Protestant de la Trémoille family. The name Commequiers appears as Quemeiquiers in old French.

The ruins stand beside a broad expanse of water in Commequiers, in the Vendée. The site is registered as a historical monument and is open to visitors; the curtain walls are broken and the tops of the towers ragged, so watch your footing on uneven stone. The Amis du Vieux Château hold events here, including a two-day "Médiévales" festival with period costumes.

The castle was built with white Sallertaine stone, a local limestone whose pale blocks still show in the surviving towers. The octagonal enceinte was articulated by round towers at its angles, and the whole complex was surrounded by a wide expanse of water. In 2018 the site was selected by the mission to identify endangered immovable heritage.