Answer:
George Washington was the first president who proclaimed a thanksgiving day.
Step-by-step explanation:
President George Washington established that the thanksgiving day would be on Thursday, November 26, 1789.
There was a resolution created by Elias Boudinot in Congress to request the United States president the establishment of prayer and thanksgiving day. Anti-Federalists did not like the idea of creating this resolution because they considered that the central government was acquiring so much power.
Finally, the resolution was approved by the House as well as the Senate. During the day of thanksgiving, president George Washington was at St. Paul's Chapel in New York and he gave beer and food to debtors who were in jail.