What are examples of how cultural geography may have affected the Great Migration in the US?

The factors which are examples of how physical geography may have affected the great migration into the United States are;

The factors which are examples of how physical geography may have affected the great migration into the United States are;•Rivers and oceans that affected transportation patterns

The factors which are examples of how physical geography may have affected the great migration into the United States are;•Rivers and oceans that affected transportation patterns•Mountains that affected rainfall patterns and settlements