March 20, 1803 | Letter Thomas Jefferson to Albert Gallatin, March 20, 1803 As Jefferson and Albert Gallatin plan Lewis and Clark's expedition, questions over geography and cartography continue as Jefferson reveals his familiarity with maps of the West.
April 13, 1803 | Letter Albert Gallatin to Thomas Jefferson, April 13, 1803 Albert Gallatin responds to Jefferson's planned instructions to Lewis by stressing the importance of evaluating the suitability of the parts of the trans-Missouri region not included in the Louisiana Purchase. He wonders if British appropriation of the region is a possibility.