Another trivial tidbit is that the large house overlooking Arlington National Cemetery is the Lee-Custis Mansion (also called the Arlington House or the Robert E Lee Memorial). Built by George Washington's step-grandson (a Custis), whose daughter married Robert E. Lee. At the end of the Civil War, the grounds of the mansion were selected as the site of the National Cemetery, in part to ensure that Lee would never again be able to return the home of his wife & family. George & Robert were related husband of a step-great-granddaughter.
T.J. & Martha had six children, but only two survived to adulthood - Martha and Mary. Three girls and a still-born son were the other 4.
It is alleged that Jefferson fathered children with one of his slaves, Sally Hemings. Modern DNA testing has been used to indicate that a male in Jefferson's bloodline did father a child by Sally.
next: James & Dolley Madison
p.s. Sorry, I live in Northern Virginia & work in the shadow of the Capitol. Exposed to this stuff continuously.