[Free Registration/Login Required] Thanksgiving Day is a national holiday in the United States. In 1621, the Plymouth colonists and Wampanoag Native Americans shared an autumn harvest feast that is acknowledged today as one of the first Thanksgiving celebrations in the colonies. For more than two centuries, days of thanksgiving were celebrated by individual colonies and states. It wasn't until 1863, in the midst of the Civil War, that President Abraham Lincoln proclaimed a national Thanksgiving Day to be held each November.