What factors contributed to American economic growth from 1820 to 1860?

Answer 1

Many factors, 2 of the major ones are:

Expansion of the American Territory - Went from everyone living mostly East of the Appalachian mountains to thousands of people living in the Oregon and California territories, in a matter of a few decades. The entire area from Texas to California was taken over, post-Mexican war, and the Great Plains were, if not taken over and homesteaded, were traveling routes.

there were many new inventions - The Cotton Gin and the Reaper allowed cotton to be cleaned faster and grain/food crops to be harvested faster, thus either cutting down on the amount of man hours needed, or allowing the same number of man hours to create many times the amount of product. The Steam Boat and Steam powered Train allowed people and goods to travel further distances, cheaper and faster, with less risk of harm. Large scale manufacturing (aka "factories") had people living closer to their job, and receiving a regular income, so they began spending a regular income on rent and food. It also created more goods faster and cheaper, so that either more could be sold/traded or the profit margin could be higher, changing the economy with having one or two people receiving all of the profits. The Erie canal was "invented" giving greater travel area and trading area, and the Telegraph allowed everyone to communicate with each other much faster. (Messages such as "All the grain down here is ruined, buy more now" conceivably could have happened, with short term changes due to the economy in response... but seriously, the ability to communicate over vast areas is almost always good for the economy/country)