Upper Canada partially abolished slavery in 1793

That happened in what became later Ontario. The Act Against Slavery "banned the importation of slaves and mandated that children born henceforth to female slaves would be freed upon reaching the age of 25.". The then lieutenant governor of Upper Canada, John Graves Simcoe, was a Christian supporter of the abolition of slavery.

One more reason why the American Civil War was unnecessary if the abolition of slavery was the cause (or was it to prevent secession?). The abolition of slavery was already ongoing and progressing in Western countries (e.g. France 1794, Denmark-Norway 1792/1803, Poland 1794, United Kingdom 1807). It was only a matter of time that slavery would also be abolished in the United States.