Château de Plancy, Medieval castle in Plancy-l'Abbaye, France.

Château de Plancy is a medieval fortified residence in the Aube valley featuring stone construction, encircling moats, and an associated chapel. The complex demonstrates the practical layout of a feudal stronghold designed to control the surrounding territory from its riverside location.

The castle of Plancy grew out of a medieval fortified castle and was the seat of a barony held from the counts of Troyes. Gillette is named lady of Plancy in 1080, and Hugues de Plancy appears in charters of 1135, 1146 and 1168. The La Croix family held Plancy from 1507 to 1654, and in May 1656 the barony was raised to a marquisate for Henri du Plessis-Guénégaud, registered in 1657 and 1658.

The barony of Plancy was raised to a marquisate in May 1656 for Henri du Plessis-Guénégaud, whose mother Marie de La Croix descended from the La Croix family that held Plancy from 1507 to 1654. The title passed through the Godard d'Aucour family, including Adrien Godard d'Aucour, marquis de Plancy and préfet, and his sons Charles and Auguste, both députés.

The site sits along the Aube river in a rural valley setting that can be accessed from nearby towns. Visitors should be prepared for outdoor conditions and uneven terrain when exploring the grounds.

The castle keep was built of stone from an early date, and the fortified complex included moats, ramparts and a collegiate church served by canons of Saint-Laurent. Nicolas de Plancy, who died in 1392, and his wife Eudelene lie buried in the Notre-Dame-en-Vaux collegiate church at Châlons-en-Champagne.