What was the name of the ridge where Wellington deployed his army at Waterloo?

Wellington deployed his army on the Mont-Saint-Jean ridge at Waterloo. The low escarpment ran roughly east–west south of the village of Waterloo and gave the Allied army a strong defensive position.

Wellington placed much of his infantry just behind the crest, using the reverse slope to hide troops from French artillery and commanders. The ridge also overlooked the Brussels road, an important route toward the Allied army’s rear. Strongpoints such as Hougoumont and La Haye Sainte protected parts of the position in front of the main line.

The name can cause confusion because the battle is known by several local names. French sources often called it the Battle of Mont-Saint-Jean, while Prussian accounts used La Belle Alliance. Waterloo became the standard English name because Wellington’s headquarters and the Allied retreat route were associated with the nearby village.

Napoleon’s attacks repeatedly struck the Allied position during 18 June 1815. The ridge held until Prussian forces arrived on Wellington’s flank, helping turn the battle into a decisive French defeat.