A blockhouse was a wooden fortification with ports or loopholes for defensive fire and, observation.  It was usually built of logs or squared timber.  Typically, a blockhouse had a projecting upper story.  Also, it had loopholes for muskets. It was generally isolated.  Often, it did not have a palisade around it.

In 1764, to protect the portage from Native American ambushes, the British army constructed one log work and 10 blockhouses along the portage from Fort Schlosser to the top of the Niagara Escarpment.