Mont-Saint-Jean is a hamlet located 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.
Mont-Saint-Jean is on the reverse slope of the escarpment where the Battle of Waterloo was fought, and is the name Napoleon Bonaparte gave to the battle (la bataille de Mont-Saint-Jean). At the time of the battle there was a farm called Mont-Saint-Jean Farm, on the Charleroi–Brussels road about halfway between the edge of the escarpment and the village.
In the novel Les Miserables 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.
Coordinates: 50°41′27″N 4°24′22″E / 50.69083°N 4.40611°E