In case you're wondering about the origin of the holiday, here's a recap below:
This is the origin of our annual Thanksgiving Day celebration. Congress of the United States has proclaimed National Days of Thanksgiving to Almighty God many times throughout the following years. On November 1, 1777, by order of Congress, the first National Thanksgiving Proclamation was proclaimed, and signed by Henry Laurens, President of Continental Congress. The third Thursday of December, 1777 was thus officially set aside:
"…for solemn thanksgiving and praise. That with one heart and one voice the good people may express the grateful feelings of their hearts, and consecrate themselves to the service of their Divine Benefactor;… and their humble and earnest supplication that it may please God, through the merits of Jesus Christ, mercifully to forgive and blot them (their manifold sins) out of remembrance… That it may please Him… to take schools and seminaries of education, so necessary for cultivating the principles of true liberty, virtue and piety under His nurturing hand, and to prosper the means of religion for the promotion and enlargement of that kingdom which consisteth of 'righteousness, peace and joy in the Holy Ghost'…"
Then again, on January 1, 1795, our first United States President, George Washington, wrote his famed National Thanksgiving Proclamation, in which he says that it is…
"…our duty as a people, with devout reverence and affectionate gratitude, to acknowledge our many and great obligations to Almighty God, and to implore Him to continue is… our duty as a people, with devout reverence and affectionate gratitude, to acknowledge our many and great obligations to Almighty God, and to implore Him to continue and confirm the blessings we experienced…"
Thursday, the 19th day of February, 1795 was thus set aside by George Washington as a National Day of Thanksgiving.
Many years later, on October 3, 1863, Abraham Lincoln proclaimed, by Act of Congress, an annual National Day of Thanksgiving "on the last Thursday of November, as a day of Thanksgiving and Praise to our beneficent Father who dwelleth in the heavens." In this Thanksgiving proclamation, our 16th President says that it is…
"…announced in the Holy Scriptures and proven by all history, that those nations are blessed whose God is the Lord… But we have forgotten God. We have forgotten the gracious hand which preserved us in peace and multiplied and enriched and strengthened us, and we have vainly imagined, by the deceitfulness of our hearts, that all these blessings were produced by some superior wisdom and virtue of our own… It has seemed to me fit and proper that God should be solemnly, reverently and gratefully acknowledged, as with one heart and one voice, by the whole American people…"Source page: http://www.christiananswers.net/q-eden/ednkc002.html