In 1863, President Abraham Lincoln proclaimed Thanksgiving to be a holiday. President Franklin Delano Roosevelt set the date by signing a bill in 1941. It declared Thanksgiving to be celebrated on the fourth Thursday of November every year.
The History website states that in 1817, New York was the first state to adopt Thanksgiving officially as a holiday. In 1827, notable author and editor Sarah Josepha Hale launched a campaign to establish Thanksgiving as a national holiday. Her crusade lasted for 36 years and consisted of editorials and letters to governors, senators and presidents. Finally, during one of his Civil War proclamations, Abraham Lincoln announced that Thanksgiving was a holiday.