The American frontier , also known as the Old West , and popularly known as the Wild West , encompasses the geography, history, folklore, and culture associated with the forward wave of American expansion in mainland North America that began with European colonial settlements in the early 17th century and ended with the admission of the last few contiguous western territories as states in This era of massive migration and settlement was particularly encouraged by President Thomas Jefferson following the Louisiana Purchase , giving rise to the expansionist attitude known as " manifest destiny " and historians' " Frontier Thesis ".
The legends, historical events and folklore of the American frontier, known as the frontier myth , have embedded themselves into United States culture so much so that the Old West, and the Western genre of media specifically, has become one of the defining features of American national identity.
Historians have debated at length as to when the frontier era began, when it ended, and which were its key sub-periods. Census Bureau would stop recording western frontier settlement as part of its census categories after the U. Others, including the Library of Congress and University of Oxford , often cite differing points reaching into the early s; typically within the first two decades before American entry into World War I.
This period includes historical events synonymous with the archetypical Old West or "Wild West" such as violent conflict arising from encroaching settlement into frontier land, the removal and assimilation of natives, consolidation of property to large corporations and government, vigilantism, and the attempted enforcement of laws upon outlaws.
In , the Superintendent of the Census, William Rush Merriam stated: "Up to and including the country had a frontier of settlement, but at present the unsettled area has been so broken into by isolated bodies of settlement that there can hardly be said to be a frontier line. In the discussion of its extent, its westward movement, etc. A frontier is a zone of contact at the edge of a line of settlement. Theorist Frederick Jackson Turner went deeper, arguing that the frontier was the scene of a defining process of American civilization: "The frontier," he asserted, "promoted the formation of a composite nationality for the American people.
