Thanksgiving was originally an American holiday that enabled people to celebrate being thankful for what they had. It later spread around the United Federation of Planets and was still celebrated in the 2370s.
In 2372, Benjamin Sisko invited the entire senior staff of Deep Space 9 to Thanksgiving dinner. The Captain had been growing vegetables for months to serve at the dinner. A year later, Michael Eddington told Sisko that he thought his former commanding officer had added too much tarragon to the stuffing. (DS9: "Blaze of Glory")