How did immigration and westward expansion impact geographic patterns in the united states?

The Westwards expansion meant that the United States acquired more lands. This meant that the demand for civilians (farmers) increased in order to be able to maintain these lands without the vast interference of the military.
As a result of this, huge amounts of people , especially Europeans , immigrated there in the second half of the 19th century.
The resources of the US increased, both agricultural products as well as gold, timber and silver as a result of this.
However, this aggravated the divide between north and south, leading to an acceleration in the onset of the Civil War.