According to Wikipedia, thanksgiving became an official Federal holiday in 1863, when, during the Civil War, President Abraham Lincoln proclaimed a national day of “Thanksgiving and Praise to our beneficent Father who dwelleth in the Heavens”, to be celebrated on the last Thursday in November.
On December 26, 1941, President Franklin D. Roosevelt signed a joint resolution of Congress changing the national Thanksgiving Day from the last Thursday in November to the fourth Thursday.
So the holiday we know today as Thanksgiving was done in 1941.
And Lincoln was not our President in 1863. Jefferson Davis was President ;)
I live 2 miles from a traditional Athabaskan Village on the upper Yukon; pretty close to all our Indians here. They always have a communal Thanksgiving Celebration at the Hall which is open to everybody. Lots of Turkey and local meat & fish, fry bread, moose head soup, on and on. Just a nice semi potlatch to give thanks to the Creator or God and get together. Indians are quite patriotic and consider themselves as American as any of us. In fact, they see all us White People as no different than the Mexicans crossing our Southern Border. The Indians are the first Americans, we all are just Johnny come lately immigrants, no joke.