David, thanks for this confirmation and additional information. I just returned from Nashville and had one day at the Tennessee Archives where I spent all my time in the Wilkes/Oglethorpe GA section. I found William Hammett in a book called "Early Warrants for survey in the Ceded Lands" where he's referred to as "from SC" and received 200 acres of land on Beaver Creek 1/13/1774. He's also in the 1790 Census of Wilkes County GA along with Sitha, Jessee and James, all in the Little River, Kettle Creek area. I found another ancestor of mine, John Johnson, listed as a participant in the Battle of Kettle Creek.
A booklet I have by Oliver Weaver says Sitha Bethel Hammett died March 11, 1790. Do you have that? If so, she died after she paid her taxes that year.
Where do you have Sitha Hammett Leftwich in 1808? She would have been Lowe then, right? Do you know anything more about her?