Taken from his bio at Wikpedia:
Although he was born into one of the wealthiest families in the United States, Thomas Jefferson was deeply in debt when he died. His possessions were sold at auction.
Here’s more:
He was a successful lawyer, though his professional income was only a supplement. He had inherited a considerable landed estate from his father, and doubled it by a happy marriage on Jan. 1, 1772, to Martha Wayles Skelton. However, his father-in-law’s estate imposed a burdensome debt on Jefferson. He began building Monticello before his marriage, but his mansion was not completed in its present form until a generation later. Jefferson’s lifelong emphasis on local government grew directly from his own experience. He served as magistrate and as county lieutenant of Albemarle county. Elected to the House of Burgesses when he was 25, he served there from 1769 to 1774, showing himself to be an effective committeeman and skillful draftsman, though not an able speaker.
snip
Jefferson had long been troubled by debt, and the failure of a friend whose note he had endorsed brought him to virtual bankruptcy. But he was rich in honor, friendship, and domestic happiness when he died at Monticello on July 4, 1826 just hours before John Adams, on the 50th anniversary of the Declaration of Independence.
Source:http://www.theamericanrevolution.org/ipeople/tjeff.asp