Thanksgiving Day is a holiday marked annually in the USA since 1863. The earliest celebrations were marked in 1598 in Texas as well as in 1619 in Virginia. The origin of this day being a celebration of harvest by the pilgrims who lived in Plymouth in 1621. Their first festival was in 1623. In this year, they gave thanks to God for rains that had ended a disastrous drought. Back then the celebrations were in the form of a church service and did not entail any feasting.
Later in the 1600s, this celebration become more common, especially after bountiful harvests. Consequently, it became an annual event. Despite this, the day was celebrated by different communities on separate days.
In other instances, there was more than one Thanksgiving day every year. The date was later harmonized to be the 4th Thursday of November every year by President George Washington in 1789.