Lacolle Mill Blockhouse, also known as, Blockhaus de la rivière-Lacolle, is a blockhouse located in Saint-Paul-de-l'Île-aux-Noix, Quebec. It was the location for the Battle of Lacolle Mills (1814). Built around 1781, the blockhouse was part of the British colonies defence network. While protecting the saw mill and the lighthouse built on the river, the Blockhouse was used as an outpost by the British Army on assignment in the Haut-Richelieu region and on Lake Champlain.