Sarah Josepha Hale, a 74-year-old magazine editor, wrote a letter to Lincoln on September 28, 1863, urging him to have the "day of our annual Thanksgiving made a National and fixed Union Festival." She explained, "You may have observed that, for some years past, there has been an increasing interest felt in our land to have the Thanksgiving held on the same day, in all the States; it now needs National recognition and authoritive fixation, only, to become permanently, an American custom and institution."

Prior to this, each state scheduled its own Thanksgiving holiday at different times, mainly in New England and other Northern states. President Lincoln responded to Mrs. Hale's request immediately, unlike several of his predecessors, who ignored her petitions altogether. In her letter to Lincoln she mentioned that she had been advocating a national thanksgiving date for 15 years as the editor of Godey's Lady's Book. George Washington was the first president to proclaim a day of thanksgiving, issuing his request on October 3, 1789, exactly 74 years before Lincoln's.

The document below sets apart the last Thursday of November "as a day of Thanksgiving and Praise." According to an April 1, 1864, letter from John Nicolay, one of President Lincoln's secretaries, this document was written by Secretary of State William Seward, and the original was in his handwriting. On October 3, 1863, fellow Cabinet member Gideon Welles recorded in his diary how he complimented Seward on his work. A year later the manuscript was sold to benefit Union troops.