Lucy Jefferson Lewis, née Lucy Jefferson (October 10, 1752 – 1811) was a younger sister of United States President Thomas Jefferson and the wife of Charles Lilburn Lewis.
Born in Albemarle County, Virginia, she was the eighth of Peter Jefferson and Jane Randolph Jefferson's 10 children. She was nine years younger than her brother Thomas Jefferson. She was born into an elite planter family and would have been educated at home by her mother, together with her sisters. Their father died when they were young.
At age 17, Jefferson married her first cousin, Charles Lilburne Lewis, on September 12, 1769. He was related to Meriwether Lewis, who would help lead the Lewis and Clark Expedition. The couple eventually had eight children: Randolph, Isham, Jane Jefferson, Lilburne, Mary Randolph, Lucy B., Martha, and Ann (Nancy).c/e
Jane and Mary had married before 1806 and established their own households. The remainder of the Lewis family moved to Livingston County, Kentucky in 1806 or 1808, following their grown sons Randolph and Lilburne and their families. Charles and Lucy Lewis built a plantation called "Rocky Hill" near the present-day town of Smithland. Lucy's older brother Thomas Jefferson took an interest in the education of her sons, and encouraged them in their studies.
(Thomas Jefferson had named a daughter, Lucy Elizabeth Jefferson I (1780–1782), after his sisters Lucy and Elizabeth. After she died as an infant, he named his next daughter after Lucy and Elizabeth as well, as was the custom. The second Lucy died at the age of 3 of whooping cough while her father was serving in Paris in the late 1780s as US Minister to France.)
Lucy Jefferson Lewis died in 1811. She was buried on the grounds of the Rocky Hill plantation, but the gravesite has been lost. The estate is now in ruins.