November 29, 1782 | Letter Arthur Campbell to Thomas Jefferson, November 29, 1782 Arthur Campbell writes to Thomas Jefferson about fossil finds in the West and possible a possible western border that may result from negotiations with the British.
January 24, 1784 | Letter Thomas Jefferson to Thomas Hutchins, January 24, 1784 Thomas Jefferson writes to geographer Thomas Hutchins with questions and remarks about one of Hutchins' pamphlets, "A Topographical Description of Virginia, Pennsylvania, Maryland and North Carolina, Comprehending the Rivers Ohio, Kenhawa, Sioto, Cherokee, Wabash, Illinois, Mississippi, &c...With a Plan of the Rapids of the Ohio, A Plan of the Several Villages in the Illinois Country, a Table of the Distances Between Fort Pitt and the Mouth of the Ohio." In his remarks, Jefferson notes several mistakes in the work.
February 11, 1784 | Letter Thomas Hutchins to Thomas Jefferson, February 11, 1784 Thomas Hutchins responds to Thomas Jefferson's January 24, 1784 note questioning calculations made in one of Hutchins' pamphlets, "A Topographical Description of Virginia, Pennsylvania, Maryland and North Carolina, Comprehending the Rivers Ohio, Kenhawa, Sioto, Cherokee, Wabash, Illinois, Mississippi, &c...With a Plan of the Rapids of the Ohio, A Plan of the Several Villages in the Illinois Country, a Table of the Distances Between Fort Pitt and the Mouth of the Ohio."
March 1, 1784 | Report Resolutions from the Committee for the Western Territory, March, 1, 1784. With Jeremiah Townley Chase and David Howell, Thomas Jefferson issues recommendations for the division and government of the western edges of United States territory. The preferred boundaries of future states are laid out and vaguely classical and Indian names are given the various regions. Congress did not adopt the Ordinance as Jefferson submitted it, primarily rejecting the abolition of slavery in the region and Jefferson's nomenclature. As passed by Congress, it became the Ordinance of 1784.
May 21, 1784 | Letter Thomas Jefferson to James Monroe, May 21, 1784 Thomas Jefferson worries about the evolving western borders and territory of the United States.
January 23, 1793 | Letter American Philosophical Society Members Subscribe to Andre Michaux's Expedition Thomas Jefferson's draft of the pledge of the subscribers to the Andre Michaux expedition.
January 23, 1793 | Letter Thomas Jefferson to Andre Michaux, January 23, 1793 Thomas Jefferson's instructions for Andre Michaux's proposed western expedition.
October 20, 1802 | Report John Watkins to the American Philosophical Society, via Benjamin Smith Barton, read January 1, 1803 Dr. John Watkins' letter to Benjamin Smith Barton is an interesting catalog of the flora and fauna of the northern parts of the Louisiana Territory. The inclusion of this missive in theTransactions of the American Philosophical Societydemonstrates the importance of science in the West to the members of the Society.
January 18, 1803 | Report Thomas Jefferson to United States Congress, January 18, 1803 Thomas Jefferson's confidential report to Congress planned westward expansion and the United States' relationship with Native Americans.
February 27, 1803 | Letter Thomas Jefferson to Benjamin Smith Barton, February 27, 1803 Thomas Jefferson informs Benjamin Smith Barton of Meriwether Lewis' upcoming journey, excited at the prospect of the scientific advances that will result.
February 28, 1803 | Letter Thomas Jefferson to Benjamin Rush, February 28, 1803 Thomas Jefferson informs Benjamin Rush of Meriwether Lewis' upcoming trip west, asking Rush to assist Lewis in any way possible. Jefferson then details his ongoing digestive problems.
February 28, 1803 | Letter Thomas Jefferson to Caspar Wistar, February 28, 1803 Jefferson informs Wistar of the upcoming expedition and of his faith in Meriwether Lewis.
March 2, 1803 | Letter Thomas Jefferson to Robert Patterson, March 2, 1803 Thomas Jefferson writes to Robert Patterson of the planned expedition west, asking him to help prepare Meriwether Lewis for taking geographical measurements.
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.
April 3, 1803 | Letter Meriwether Lewis to Thomas Jefferson, April 3, 1803 Meriwether Lewis writes to Jefferson regarding his preparations, including his many communications with men of science. Lewis includes his plans for a collapsible boat.
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.
May 13, 1803 | Letter Bernard Lacépède to Thomas Jefferson, May 13, 1803 Bernard Lacépède applauds Jefferson's dedication to exploration and expansion, predicting success and the expansion of United States trade and communication because of it.
June 20, 1803 | Letter Thomas Jefferson to Meriwether Lewis, June 20, 1803 Thomas Jefferson issues detailed instructions to Meriwether Lewis, addressing every aspect of the upcoming expedition.
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.
October 3, 1803 | Letter Meriwether Lewis to Thomas Jefferson, October 3, 1803 While pausing to provision his expedition, Meriwether Lewis writes to Thomas Jefferson about the scientific explorations at Big Bone Lick and his plans for the trip westward.
October 21, 1803 | Letter William Dunbar to Thomas Jefferson, October 21, 1803 William Dunbar responds to Thomas Jefferson's September 21 letter regarding the Spanish presence in Florida and the Gulf Coast and the surveys conducted by the Spanish in that region. He also praises Daniel Clark's summation of the population of the Lousiana Territory and suggests a representative from that region appear before Congress, but notes that the Spanish government is unlikely to allow such a measure to take place as long as the territory is in their hands.
October 21, 1803 | Letter William Dunbar to Thomas Jefferson, October 21, 1803 William Dunbar writes to Thomas Jefferson regarding the Spanish presence in Florida and the Gulf Coast and the surveys conducted by the Spanish in that region. He also praises George Rogers Clark's summation of the population of the Lousiana Territory and suggests a representative from that region appear before Congress, but notes that the Spanish government is unlikely to allow such a measure to take place as long as the territory is in their hands.
November 16, 1803 | Letter Thomas Jefferson to Meriwether Lewis, November 16, 1803 Thomas Jefferson updates Meriwether Lewis on political activity around the event of the Louisiana Purchase. Jefferson includes notes from the explorer Truteau that detail population and activities of some native groups living west of the Mississippi.
January 22, 1804 | Letter Thomas Jefferson to Meriwether Lewis, January 22, 1804 Thomas Jefferson informs Meriwether Lewis of the steps the United States is taking to consolidate its position in the land along the Mississippi.
March 13, 1804 | Letter Thomas Jefferson to William Dunbar, March 13, 1804 Thomas Jefferson thanks William Dunbar for his letter of January 28, promising to forward his paper on the Mississippi River to the American Philosophical Society. Jefferson then writes a detailed discussion of the science of water in a river like the Mississippi. Jefferson also relates his plans for directing surveying parties to the Mississippi and Ohio Rivers, in addition to explorations of the Red and other more southern waterways. Jefferson concludes with speculations on the future of the Lousiana Territory.
April 6, 1804 | Report William Dunbar to the American Philosophical Society, via Thomas Jefferson, read April 6, 1804. The Mississippi River, its delta, and the surrounding region receive detailed attention from William Dunbar in this report forwarded to the APS by Thomas Jefferson.