The USA celebrates "thanksgiving" on a different date, to commemorate the following:

In 1637, the Pequot tribe of Connecticut gathered for the annual Green Corn Dance ceremony. Mercenaries of the English and Dutch attacked and surrounded the village; burning down everything and shooting whomever try to escape. The next day, Newell notes, the Governor of Massachusetts Bay Colony declared: "A day of Thanksgiving, thanking God that they had eliminated over 700 men, women and children." It was signed into law that, "This day forth shall be a day of celebration and thanksgiving for subduing the Pequots."