Lacolle Mills Blockhouse, building in Quebec, Canada

Lacolle Mills Blockhouse is a square, two-storey timber-framed structure overlooking the Lacolle River. Its walls are squared half-timber stacked horizontally, pierced with loopholes for firing while protected, and the second floor is cantilevered under a pavilion roof. A stone hearth stood at the centre for heating. The British military built over 25 forts of this type in Lower Canada between 1760 and 1840.

Built around 1781 as part of the British colonies' defensive network, the blockhouse guarded a stone watermill and a lighthouse on the Lacolle River. In 1812 Canadien militia and Kahnawake Mohawk warriors repelled an American force under Major General Henry Dearborn. In 1814 a garrison of 80 men of the 13th Regiment of Foot, with a Congreve rocket detachment of the Royal Marine Artillery, later reinforced by Canadian Voltigeurs and the grenadier company of the Canadian Regiment of Fencible Infantry, held the blockhouse and mill against 4,000 Americans under Major General James Wilkinson. It was included in the Battle of Lacolle Mills National Historic Site in 1923 and designated a cultural heritage building in 1960.

The blockhouse is a timber-framed structure, not stone: its walls are squared half-timber stacked horizontally, with loopholes for firing and a stone hearth at the centre for heat. It was one of over 25 forts of this type the British military built in Lower Canada between 1760 and 1840. The name Lacolle Mills refers to the watermill and lighthouse it guarded on the Lacolle River.

The site is located near the river and easy to reach, making it suitable for walks along the riverbank as well. Visiting is best in good weather and hours are limited, so checking availability beforehand is recommended.

The blockhouse is one of over 25 forts of this timber type the British military built in Lower Canada between 1760 and 1840. Its squared half-timber walls are stacked horizontally, and the second floor overhangs the first under a pavilion roof, a detail visible from outside.