Many immigrants and settlers had economic opportunities in the west. Because of the rich soil, many settlers became farmers. And the railroads also provided construction jobs to help expand transportation
The US had several advantages like railroads for faster transportation, the telegraph for faster communication, better leadership, more money, and better resources
Indian Removal Act was issued by President Jackson. It 'moved' five major tribes into an Indian Territory in present-day Oklahoma. The Trail of Tears is the famous of the latter