Castle Frank is the name of a subway station in Toronto that has connections to the early days of the region as a British Colony. Lt Governor John Graves Simcoe had several children, but greatly favoured the youngest, his only son Francis.

The Simcoe family built a log cabin near the current site of Castle Frank Station as a summer cottage and place for the children to play. He named it "Castle Frank" after his beloved Francis. The cottage was high enough up the escarpment of the Don Valley to not be swarmed by the mosquitos by the river and provided a lovely scenic view of the area.

John became ill in 1796 and returned to England with his family. Young Francis never returned to his castle, and was killed in action in Spain in 1812. Careless (and probably cold) fishermen burned Castle Frank to the ground in 1829.