John Wayles Jefferson, was an American businessman and Union Army officer in the American Civil War. He is believed to be a grandson of Thomas Jefferson; his paternal grandmother is Sarah (Sally) Hemings, Thomas Jefferson's mixed-race slave and half-sister to his late wife.

Eston Hemings Jefferson was born into slavery at Monticello, the youngest son of Sally Hemings, a mixed-race enslaved woman. Most historians who have considered the question believe that his father was Thomas Jefferson, the third President of the United States. Evidence from a 1998 DNA test showed that a descendant of Eston matched the Jefferson male line, and historical evidence also supports the conclusion that Thomas Jefferson was probably Eston's father. Many historians believe that Jefferson and Sally Hemings had six children together, four of whom survived to adulthood. Other historians disagree.