U.S. President Abraham Lincoln declared Thanksgiving Day a national holiday in 1863. He was probably swayed in part by magazine editor Sarah Josepha Hale—the author of the nursery rhyme "Mary Had a Little Lamb"—who had suggested Thanksgiving become a holiday, historians say.
In 1941 President Franklin Roosevelt established the current date for observance, the fourth Thursday of November.
Thanksgiving Day Facts: Pilgrims, Dinner, Parades, More