La Mothe-en-Bassigny, Archaeological site and historical monument in Haute-Marne, France.

La Mothe-en-Bassigny is a ruined citadel on a 506-metre hill between Outremécourt and Soulaucourt-sur-Mouzon. The site is now forested, with scattered piles of stone marking the former stronghold. The hilltop is enclosed by thick, faceted ramparts with pointed bastions, and the interior ground is uneven and open.

The site was founded in the early 13th century and grew rapidly into a major trading hub. After enduring multiple attacks during the conflicts between France and its neighbors, the fortress was ultimately destroyed.

The name comes from the motte, the raised mound on which the stronghold stood. Two assemblies of the Estates met here in 1506 and 1580 to draft the custom of Bassigny. Since 1897 a monument funded by subscription stands where the government palace square once was, and the Association pour La Mothe has worked since 2005 to safeguard the ruins.

The site lies in open countryside and is accessible on foot, though it can become muddy after rain. The best time to visit is during warmer months when grass is short and the remains are easier to see.

After the 1645 surrender, Mazarin had not only the fortifications but every building of La Mothe razed, though the surrender terms had promised otherwise. The last parish register entry, a baptism signed by vicar Anthonie Vigneron on 8 September 1645, records the town being razed to its foundations. Around 3,000 inhabitants were expelled.