Martha Skelton Jefferson was the wife of Thomas Jefferson from 1772 until her death in 1782. She served as First Lady of Virginia during Jefferson's term as governor from 1779 to 1781. She died in 1782, 19 years before he became president.
Of the six children born to Thomas and Martha, only two survived to adulthood, Martha and Mary. Martha died four months after the birth of her last child. The couple's letters to one another were burned, though by whom is unknown, and Thomas rarely spoke of her, so she remains a somewhat enigmatic figure. (Similarly, Jefferson did not speak much of his mother, Jane Randolph Jefferson.)
As a widower, Thomas had a long-standing relationship and children with Martha's half-sister, Sally Hemings, an enslaved woman who was three-quarters white by descent.