Many online genealogies have a William Shannon, born 1812, as a son of John Shannon (~1755-1815). This is almost certainly an error. There is no evidence that John had any children that young, and we now know that his actual son William from the estate records was in Georgia in the 1830’s, with several sons listed as beneficiaries of a number of slaves purchased for that purpose. My belief is that William Shannon, born 1812, who shows up in Kemper County, MS and later in Yazoo county is the son of Thomas Shannon (~1785-1830+) listed on the 1830 census in Pickens Co., AL. However, another William Shannon of the correct age shows up in Tippah County, MS (or McNairy County, TN) who was probably the son of Owen Shannon. However, the family that later moves to Yazoo Co., MS appears to have been the one from Kemper County.
Bad Genealogy Rant: Thomas Shannon (1730-1794) and descendants. 