King George III hoped the Proclamation of 1763 would stop

In response to Pontiac's Rebellion, a revolt of Native Americans led by Pontiac, an Ottawa chief, King George III declared all lands west of the Appalachian Divide off-limits to colonial settlers. This royal proclamation, issued on October 7, 1763, closed down colonial expansion westward beyond Appalachia.

The United States changed dramatically in its first half century. In 1776 the U.S. consisted of THIRTEEN COLONIES clustered together on the eastern seaboard. By 1821 eleven new states had been added from Maine to Louisiana. This geographic growth and especially the political incorporation of the new states demonstrated that the United States had resolved a fundamental question about how to expand. This growth not only built upon the Louisiana Purchase, but included military intervention in SPANISH FLORIDA which the United States then claimed by treaty in 1819.

The new shape of the nation required thinking about the United States in new ways. For instance, a classic text on American geography in 1793 taught that the United States was composed of three basic divisions: northern, middle, and southern. But the 1819 edition of that same book included a new region because western states and territories needed recognition as well. By 1820, over two million Americans lived west of the APPALACHIAN MOUNTAINS.

The growing regional distinctiveness of American life was complex. Four basic regions with distinct ways of life had developed along the eastern seaboard in the colonial period. Starting in the north, they were NEW ENGLAND (New Hampshire, Massachusetts, Rhode Island, and Connecticut); the MID-ATLANTIC (New York, New Jersey, and Pennsylvania); the CHESAPEAKE (Delaware, Maryland, and Virginia); and the LOWER SOUTH (the Carolinas and Georgia). As people from these regions joined new immigrants to the United States in settling the west, they established additional distinctive regions that combined frontier conditions with ways of doing things from their previous places of origin

The newly settled western lands of this period can be grouped in several ways, but four basic divisions were most evident: the BORDER AREA (Kentucky and Tennessee, the first trans-Appalachian states to join the nation), the Old Northwest (Ohio, Indiana, and Illinois), the OLD SOUTHWEST (Alabama and Mississippi), and the TRANS-MISSISSIPPI RIVER WEST (Louisiana and Missouri).