Answer:
Westward Expansion was the process of America's expansion to the west. It began with the Louisiana Purchase, followed by Lewis and Clark's expedition west. The Oregon Trail story was part of it, too. The 49er's in the California gold rush were also part of westward expansion. The pony express, a mailing system to the west through ponies were also part of it. It came to an end with the building of the transcontinental railroad.