Thanksgiving or Thanksgiving Day, presently celebrated on the fourth Thursday in November, has been an annual tradition in the United States since 1863. It did not become a federal holiday until 1941.
Thanksgiving was historically a religious observation to give thanks to God, but is now primarily identified as a secular holiday.
The First Thanksgiving was celebrated to give thanks to God for helping the pilgrims survive the brutal winter. The first Thanksgiving feast lasted three days providing enough food for 53 pilgrims and 90 Indians.