History: American Old West, United States

Acquiring the Frontier
• Advancing frontier and the Louisiana Purchase
During European settlement of North America in the 17th century, the western frontier was the crest of the Appalachian Mountains, the initial geographical impediment to expansion. While the eastern seaboard was being tamed, the area west of these mountains received little concern and speculation. After the American Revolutionary War, the conflict among European powers over the vast American continent and its riches gave way to the new nation of the United States. With peace came an impetus for westward expansion, as veterans returned to areas seen during the war, and land hungry settlers traveled to newly available lands in New York and across the Appalachians.
At the beginning of the 19th century, the American frontier was approximately along the Mississippi River, which bisects the continental United States north-to-south from just west of the Great Lakes to the delta near New Orleans. St. Louis, Missouri was the largest town on the frontier, the gateway for travel westward, and a principal trading center for Mississippi River traffic and inland commerce.