Thanksgiving s a harvest festival celebrated primarily in the United States and Canada. Traditionally, it has been a time to give thanks for a bountiful harvest . In the united states the modern Thanksgiving holiday tradition traces its origins to a 162 1 celebration at plymouth in present-day MassachusettsThanksgiving ❖ a harvest festival celebrated primarily in the United States and Canada. Traditionally, it has been a time to give thanks for a bountiful harvest. ❖ In the United States, the modern Thanksgiving holiday tradition traces its origins to a 1621 celebration at Plymouth in present-day Massachusetts