The document discusses several key issues around the closing of the American western frontier in the late 19th century, including: 1) Various groups migrated westward for opportunities including free land, profit, and manifest destiny, straining relations with native peoples and leading to conflicts over land and resources. 2) Iconic figures and groups emerged during this period like cowboys, gunslingers, miners, ranchers, settlers, and soldiers, many of whom faced hard lives and conflicts on the frontier. 3) Native American tribes suffered tremendously from loss of lands and buffalo herds, disease, and conflicts with white settlers and government policies which led to many being forced onto reservations.