Thomas Jefferson's identification with westward settlement began when his father, Peter Jefferson, and Joshua Fry drew the first correct map of their province. The mapping of the vast country that lay beyond his father's map became a lifelong interest, leading to the Northwest Ordinance and the Lewis & Clark Expedition. Jefferson's vision of "Sea to Shining Sea" was accomplished when his grandson-in-law, Nicholas P. Trist, negotiated the Treaty of Guadalupe Hidalgo in 1848.