IGI batch 7732027, p.66, lists marriage of Nathaniel Campbell and Sally Pettit on 17 Jan 1805 in Washington Co., KY. IGI batch 7829902, p.27, lists the marriage of Nathaniel Campbell and Sallie O. Pettit on the same date in Fauquier Co., VA. Since Sally's father Thomas was not in the 1810 census of Kentucky, my guess is that the second record is correct.