This course provides an expansive look at the history of U.S. exploration from 1776 to the present, examining the evolving objectives and consequences of exploration over the course of two centuries. The history of U.S. exploration is far more complex and diverse than the story that has commonly been told. The nation's explorers include women, African Americans, and Indigenous people, individuals who sought to escape from lives conscribed by discrimination and limited opportunities through adventuring. Although U.S. explorers consistently sought to advance the nation's standing, their efforts also demonstrated a marked shift in exploratory objectives over time. While explorers primarily strove to acquire and develop land in the early nineteenth century, they increasingly tried to conserve it from destruction by the early twentieth century. After the closing of the western frontier in 1890, American adventurers not only increasingly recognized the importance of preserving wilderness, but also began to explore new regions of the world to gain scientific or anthropological knowledge. In doing so, they redefined the notion of the frontier as they turned to the Artic, to air, and to space.