Alexander Mackenzie was a foreman on the construction of the Carthcart Tower and later went on to become Canada's second prime minister 1873–1878.

It was his work crew whose boat capsized while returning from Cedar Island, drowning 17 men.

The guns of Cathcart Tower covered the eastern approaches of Kingston Harbour.

[2] When war was averted, Cathcart Tower was used for a time as a barracks for soldiers garrisoned at nearby Fort Henry.

[3] The tower is reached by small water craft with a dock located on the north side of Cedar Island.