November 29, 1800 | Letter James Wilkinson to Thomas Jefferson, November 29, 1800 James Wilkinson introduces Thomas Jefferson to the work of William Dunbar and offers his own map of the Mississippi Territory.
July 13, 1801 | Letter Thomas Jefferson to William C. C. Claiborne, July 13, 1801 Thomas Jefferson writes to William Claiborne with news of his appointment as Governor of Mississippi, noting the importance of the region as "the principal point of contact between Spain and us, & also as it is the embryo of a very great state." Jefferson also warns Claiborne of the importance of encouraging the residents of Mississippi to embrace party politics similar to his.
March 14, 1803 | Letter Albert Gallatin to Thomas Jefferson, March 14, 1803 Albert Gallatin informs Thomas Jefferson of the preparations he has made for the Corps of Discovery expedition, including commissioning Nicholas King's blank projection of western North America. Gallatin demonstrates his familiarity with the work of cartographers including Arrowsmith, Delisle, and Mackenzie, assuming Jefferson has the same background knowledge.
August 9, 1803 | Letter Thomas Jefferson to John Dickinson, August 9, 1803 Thomas Jefferson expresses his pleasure at the Louisiana Purchase, and explains the importance of the territory as a buffer against Spanish expansion.
May 13, 1804 | Letter William Dunbar to Thomas Jefferson, May 13, 1804 William Dunbar thanks Thomas Jefferson for his comments about Dunbar's notes on the Mississippi River. Spain's land sales in Western Florida draw the author's attention and Dunbar offers approval of continuing explorations on America's western rivers, while bemoaning Congress' reluctance to adequately fund such expeditions.