Answer:
One reason Jefferson wanted to purchase the Louisiana Territory is for future expansion.
Step-by-step explanation:
Jefferson had read about the Northwest Passage, a way to link the Atlantic Ocean and the Pacific Ocean and thus a secured trade route. As it was at the time most of the territory west of the colonies was still controlled by the Native Americans as well as it being undeveloped, going was very slow for explorers. Having access to the Mississippi River would change so much for trade routes and Jefferson was forward thinking in knowing that securing the Mississippi River would change trade prospects in the new United States.