From the Horseblock Point website:
"The name Horseblock Point arose from an incident which occurred during the war of 1812. Local history tells us that a group of horse thieves from New York State, which can be seen immediately across the river from the front of our property, landed here and proceeded into the surrounding countryside to steal horses."
"However, they were apprehended by the local militia and elements of the British Army on this point... ."
The Horseblock Point story was also featured in a newspaper article in the Gananoque Reporter.
There's also this: Raid On Gananoque.