Canada has a long and varied relationship with Thanksgiving. Canadians have been celebrating Thanksgiving in one form or another since 1799, though the time of year and reason behind the holiday varied until about 1887 when the day of celebrating the "Blessings of an abundant harvest" were fixed, with some exceptions, on a Thursday around mid November, merging into the practice of holding it on the same day as "Armistice Day" (now known as Remembrance Day) after the First World War. By about 1931 the practice of having Thanksgiving on the second Monday in October came about and the Holiday was made official in 1957. Interestingly, Canada, unlike in the U.S., has held "Thanksgiving" days for all sorts of reasons: the end of wars, the end of Cholera, Queen Victoria's Diamond Jubilee etc. But still there was a long history of celebrating the Harvest in Canada in October and November, and that is the practice that survives until today.
Celebrating the harvest is not a foreign concept to most Pagans. In the Pagan (largely derived from the Celtic) calendar there are three major harvest festivals: Lughnasadh (Lammas), Mabon and Samhain. Thanksgiving falls almost directly between the latter two, which is not surprising either culturally or practically since this time of year is in fact when a lot of the Canadian harvesting is done. As a largely urban community as well, it is even more important to celebrate and be thankful for the bounty of the land in order to help bridge the gap between us and our food. Being respectful and thankful for the abundance around us also makes us more conscious and conscientious which promotes your own health and the health of the animals and vegetation we eat. This is a very Pagan concept.
This year, I suggest making your Thanksgiving with a little extra Pagan flare: Set a place at your table for the Goddess and the God. Thank the Goddess for the bounty of the earth, offering her a slice of pumpkin pie, an apple, some corn, potatoes and cranberries. Thank the God for providing us with meat and ask him to bless the souls of the animals who were sacrificed so we could eat. Pile his plate with turkey and gravy pour him some wine or mead as befits the Great Hunter. At the end of the meal, put some of the food outside for the local wildlife to enjoy, as well as any Fae hanging about (they really like apples and honey). If you can, bury the rest so you are giving back to the earth what it has given you.
For centuries Canadians have been observing the practice of being thankful for great fortune and bounty. Pagans have been doing the same for millennia. This year, blend the two for a truly thankful Thanksgiving.