What is thanksgiving:Thanksgiving, or Thanksgiving Day, is a public holiday celebrated on the fourth Thursday of November in the United States. It originated as a harvest festival. thanks giving has been celebrated nationally on and off since 1789, after a proclamation by George Washington. It has been celebrated as a federal holiday every year since 1863, during the American Civil War, President Abraham Lincoln proclaimed a national day to be celebrated on the last Thursday in November. Together with Christmas and the New Year when is thanksgiving, Thanksgiving 2016 is a part of the broader holiday season.Features:Happy Thanksgiving Day Quotes.thanksgiving date.