Actually, the Isaac Brigman who had the 1811 will was listed on the 1790 SC Census in Georgetown, but Fereby is not listed on the census. This Isaac was married to an Elizabeth before he ever married Fereby. There is no documented proof of Fereby's maiden name (unless you have it). The Isaac Brigman in Richmond county NC that you refer to were 2 additional Isaac Brigmans....there were 3 living at the same time.

Lisa James was correct that the Isaac Brigman with the 1811 will did have several sons who moved to IL around 1815. John, the oldest son and executor of his father's estate, did not manage the distribution of the will to the benefit of all the children. He left and took his brothers Isaac and Solomon with him. Solomon died around 1820 and Isaac died around 1835, both leaving no known issue.

Many Brigmans became respected Mormons, but this line is not one that is believed to be such.

Terri Brigman England