How was the largest level of interregional migration in the United States caused by the discussions of demographic changes within the United States?

Study of demographic changes in the United States shows that the biggest interregional migration in the history of the country was due to the opening up of the western territories.

A new world was opened up when people began to migrate west. Many people were tired, weary and beaten down from the often harsh conditions in the North East where European settlements first began popping up. The west was the land of milk and honey, winters were not so harsh, there was the gold rush, and there was opportunity for people to become landowners that had not seen this opportunity before.