The Blockhouse at Rideau Canal Narrows Lockstation overlooks the Rideau Canal. The lower storey is constructed of thick, stone masonry while the upper storey is built of squared timbers. Defence features include loopholes and a second-floor entrance accessed by an exterior stairway.
Construction of the Narrows Blockhouse began in 1832, during the period in which the Rideau Canal fulfilled a defence role for the United Canadas. The blockhouse building type was an essential element in the defence strategy for the canal, which included a major defensible building at each lock-site. The Blockhouse is one of only four that were completed on the Rideau Canal.
Part of the Rideau Canal National Historic Site, the Narrows Blockhouse is a recognized Federal Heritage Building