Thomas Jefferson was president before the civil war, making it impossible for him to send explorers to explore land acquired during the civil war. Although I am not sure, I believe that no land was acquired during the civil war. He did, though, send Meriwether Lewis and William Clark to explore the United States after the Louisiana purchase.
True
France through the Louisiana Purchase of Jefferson's presidency.
Thomas Jefferson.
Thomas Jefferson was president in 1801 through 1809
Thomas Jefferson was the President of the United States when Thomas Jefferson was the President.
Ronald Reagan.
Ronald Reagan
William Jefferson Clinton.
March 4th, 1801 through March 4th, 1809.
It was unusual because it brought about a deadlock in the House. A constitutional defect was revealed through it. Through an outdated provision in the constitution, there was a tie between the Republican candidates standing for president and the vice president between Jefferson and Aaron Burr. Finally Jefferson won.
Thomas Jefferson was hoping to find a water route through the United States to the Pacific Ocean.
The land you seek was the Louisiana Purchase
Woodrow Wilson was nicknamed "The Professor." I found this answer through a Google search so if it is incorrect, I apologize.