Period 6

Introduction

After the Civil War, the United States faced widespread disruption, yet it entered a period of rapid recovery and opportunity. Urban centers saw the rise of powerful industrialists often called “robber barons,” while the frontier remained a contested space of Plains Indians and cattlemen. During this era the nation developed the resources and infrastructure necessary to become a leading industrial power: vast deposits of iron, coal, oil, gold, and silver; extensive arable land for corn and wheat; and a steady flow of unskilled labor from immigration. These factors helped drive dramatic growth in steel and oil output and an unprecedented expansion of railroad mileage. The settlement and resource extraction of the American West supplied many of the raw materials that underpinned this industrial transformation. Those economic changes produced far-reaching social consequences for workers and reshaped the political landscape. Period 6 is therefore a significant focus for the AP U.S. History exam, accounting for roughly 10–17% of the test.