The traditional Thanksgiving holiday is traced to a sparsely documented celebration in 1621 at Plymouth which is in present-day Massachusetts. The feast was prompted by a good harvest. But the very first Thanksgiving was actually in 1623, giving thanks for the rain that ended a drought. The holiday spread to various dates in different communities and even more than once a year. The first national Thanksgiving Day was proclaimed by George Washington, the first president of the United States, on November 26, 1789.