What Was the Cause and Effect of Westward Expansion?

By Staff WriterLast Updated Mar 25, 2020 12:03:37 PM ET

The causes of westward expansion were the purchase of the Louisiana territory from France, the Lewis and Clark expedition, President Thomas Jefferson's vision of expanding into the available land to create an "empire of liberty" and a growing sense of American "manifest destiny." The effects included controversies over the slavery issue, which led to the Civil War, the persecution and extermination of Native Americans and the war with Mexico.