It should be said that Jefferson personally accumulated considerable debt. He inherited quite a bit of property, money, and yes, slaves... balanced by inheriting debt. But then he was a BIG spender too. He could not return from Europe without crate after crate of things for Monticello. Part of the reason that he often talked of abandoning public life was to get back to Virginia to improve his financial standing. I believe he died with little in the way of an estate.
I seem to recall that Jefferson went into heavy debt because of othes in his family and because his investments included signing notes for friends who defaulted. Do you know of this?