Analyze and evaluate the ways that both external and internal migration changed over time from 1830 to 1920

Cover not only why they went west, but the effects on the economy, society and Native Americans of them moving west. In terms of external immigration, you could concentrate on why people immigrated from other countries and what effects that had on the economy and the growth of cities (and the good and bad effects of that growth)

Specific evidence

push and pull factors for external migration

two pieces of specific evidence for internal and two for external