Mont-Saint-Jean (French pronunciation: [mɔ̃ sɛ̃ ʒɑ̃]) is a hamlet located in Wallonia in the province of Walloon Brabant, Belgium, south of Waterloo located partly on Waterloo and partly on Braine-l'Alleud where the National road (N5) going from Brussels to Charleroi crosses the National road (N234) going from Nivelles to Leuven.
The situation is best rendered by this eloquent albeit sober passage by an eyewitness, Sgt-Maj. Cotton : "The field of battle, after the victory, presented a frightful and most distressing spectacle.
The assistance of the town authorities was requested, in collecting and removing the wounded from the field, burying the dead, etc., as well as to restore confidence amongst the population, and allay the extreme excitement which prevailed throughout Belgium.
The clergy, as might have been expected, were foremost in their exertions to relieve the dreadful agonies of so many gallant and innocent sufferers : the highest in rank rivalled the hardier classes in performing the most trying offices for the mangled heroes that filled the hospitals, and encumbered even many private dwellings.
In the novel Les Misérables by Victor Hugo, Volume II, Book I, Chapter X is called "The Plateau of Mont-Saint-Jean" and it describes the massive French cavalry attacks on the British infantry squares situated on the reverse slope of the escarpment at the height of the battle.