Donjon des Comtes de Chaumont

Standing on a natural spur overlooking the Suize valley, the keep is the only vestige of the castle of the Counts of Champagne, the town's birthplace.

At 19 m high, this square tower has retained its medieval appearance, with walls varying in thickness from 2.60 m at the base to 1.50 m at the top.

The bossing of the stones in the lower section indicates a late date: second half of the 12th century.

Originally a defensive structure built by the lord of the castle, once topped by a hoarding, it was later used as a prison. Inscriptions engraved on the walls date back to this period.
At its foot is the Chaumont Museum of Art and History.

Listed in the supplementary inventory of historic monuments.