Answer:
One important goal accomplished by the Lewis and Clark expedition was the "mapping of the American West".
Step-by-step explanation:
In 1803 Louisiana was purchased from France by United States. Therefore before settlement, western location was needed to be examined, hence President Jefferson appointed his own private secretary named as Meriwether Lewis as a Commander in charge of the expedition while Lewis invited William Clark, his former Army superior officer to be his Co-commander.
The expedition covered the duration from May 1804 to September 1806. They did not find a waterway from the Mississippi to the Pacific, but did succeed in documenting biodiversity of region by discovering more than 100 new animals and 178 plants as well as providing 140 maps of the area.