Château de Boisy, Medieval castle in Pouilly-les-Nonains, France.

The Château de Boisy stands on the small Boisy plateau in Pouilly-les-Nonains, in the Loire department. Its three-part stone complex combines a ruined round tower and roofless wall on the left, a long central building with a steep pitched roof, three rectangular chimneys and a row of projecting corbels, and a tall round tower with a conical roof on the right. The south and east wings, the south-east round tower and the north-east square keep are classified.

Jacques Coeur acquired the castle in 1447, but after his downfall in 1455, the property passed to Guillaume Gouffier, the king's first chamberlain. Under Gouffier family rule, the castle gained its later aristocratic features.

The castle displays features from different periods, ranging from medieval fortifications to later modifications by the Gouffier family. These layers remain visible in its walls and interior layout today.

The castle stands on the small Boisy plateau in the commune of Pouilly-les-Nonains, in the Loire department of the Auvergne-Rhône-Alpes region, not in the Loire Valley or Bourgogne-Franche-Comté. The site lies in the low ground of the former canton of Saint-Haon-le-Châtel, so approach it from Pouilly-les-Nonains rather than from the village of Saint-Haon-le-Châtel itself.

The castle owes its nickname to Jacques Coeur, who bought it in 1447 but lost it after his disgrace in 1451; Guillaume Gouffier, the king's first chamberlain and the man behind his fall, acquired it in December 1455. The Simon brothers who built the keep in 1402 were not lords of Boisy despite their name.