Battle of Lacolle Mills (1812)

The Battle of Lacolle Mills on 20 November 1812 was the first of the war’s two engagements at this location (the second, in March 1814, would see Wilkinson’s final disgrace) and the first failed American attempt on Montreal. It was a confused night action in which American forces fired on each other in the darkness, the advance guard was repulsed by a small Canadian force, and the entire invasion was called off within hours.

Major General Henry Dearborn had assembled approximately 6,000 troops at Plattsburgh for an advance on Montreal. The plan called for an invasion of Lower Canada down the Lake Champlain corridor. On 19 November, an advance force crossed the border and moved toward Lacolle, where a small British outpost guarded the approach.

Major Charles de Salaberry — who would achieve his greatest fame at Chateauguay the following year — commanded the Canadian forces in the area. His Voltigeurs, Frontier Light Infantry, Indigenous warriors, and militia contested the American advance. The engagement took place in darkness, and the result was chaos.

Two American columns, advancing along parallel roads, mistook each other for the enemy and opened fire. The friendly-fire incident caused casualties on both sides and thoroughly disorganised the advance. The Canadian defenders exploited the confusion, firing from concealed positions and maintaining pressure on the disoriented Americans.

Colonel Zebulon Pike (who would later be killed at York) commanded the advance guard and attempted to press forward, but the confusion, the darkness, and the Canadian resistance proved too much. The Americans withdrew to their camp on the American side of the border.

The decisive moment came the following day, when the New York and Vermont militia refused to cross back into Canada. As at Queenston Heights a month earlier, the militia invoked their right to decline service on foreign soil. Dearborn, faced with an army that would not advance, abandoned the invasion and marched his troops back to Plattsburgh.

The first American attempt on Montreal had ended before it properly began. De Salaberry’s defence was effective, but the real obstacle was the same one that dogged American operations throughout the war: the militia system was designed for territorial defence, not for the invasion of a neighbouring country. No amount of strategic planning could overcome the structural reality that a significant proportion of the American army would not fight on foreign soil.