[Bull Snipe]

After Jefferson’s death, Martha Randolph (TJs daughter) placed Sally Hemmings on her “own time” (retired from work)
A little later, Sally was allowed to leave Monticello. She moved in with two of her sons that lived near Charlottesville. In the 1830 census, she and both of her sons were listed as white.

[Verginius Rufus]

Sally is thought to have been the half-sister of Jefferson's wife and had 3 white and 1 black grandparents. Some of her descendants definitely did "pass" for white.

Jefferson wrote that "three crosses clears the blood"--talking about children of mixed race. Since Sally's mother was half-white, Sally's children by a white father would be white by Jefferson's rule. In practice, anyone who had perceptible African ancestry was considered black (the so-called one drop rule).