It was only in the nineteenth century that this event became identified with the American Thanksgiving holiday.
The first national Thanksgiving was declared in 1777 by the Continental Congress
The holiday then reverted to being a regional observance until 1863, when two national days of Thanksgiving were declared, one celebrating the victory at Gettysburg on August 6, and the other the first of our last-Thursday-in-November annual Thanksgivings
During the second half of the nineteenth century, Thanksgiving was more commonly symbolized by its New England origins and its chief dinner constituent, the turkey, than by the Pilgrims' 1621
The association between Thanksgiving and the Pilgrims had been suggested as early as 1841 when Alexander Young identified the 1621 harvest celebration as the "first Thanksgiving