A lot of US coins
made their way into Canada. Canada's history goes back into the 1600's but they didn't get their own coinage until 1858 with cents and ten cents and 1870 with 25 cents. And those all were imported from England. Canada didn't have their own mint until 1908. Even though they were of British and/or French extraction they modeled their economy on their closest Neighbor, the US and kept their accounts in dollars and cents rather than Pounds, Shillings and Pence. This would make it natural for our coins, which had been around for over 70 years, to make their way across the border.
I'm guessing it would have been illegal to melt them down?
It was always legal to melt down Half Cents
and large cents. They weren't legal tender and there was no law forbidding it. Supposedly during times when copper prices would rise, coppersmiths would use large cents as a source of raw materials.