A frontier is a political and geographical term referring to areas near or beyond a boundary, or of a different nature.
In the United States, the frontier was the term applied by scholars to the impact of the zone of unsettled land outside the region of existing settlements of Europeans. That is, as pioneers moved into the frontier zone they were changed significantly by the encounter. That is what Frederick Jackson Turner called "the significance of the frontier." For example, Turner argued in 1893, one change was that unlimited free land in the zone was available and thus offered the psychological sense of unlimited opportunity, which in turn had many consequences, such as optimism, future orientation, shedding of restraints due to land scarcity, and wastefulness of natural resources.
Throughout American history, the expansion of settlement was largely from the east to the west, and thus the frontier is often identified with "the west". On the Pacific Coast, settlement moved eastward. In New England, it moved north.
'Frontier' was borrowed into English from French in the 15th century with the meaning "borderland," the region of a country that fronts on another country (see also marches). The use of frontier to mean "a region at the edge of a settled area" is a special North American development. (Compare the Australian "outback".) In the Turnerian sense, "frontier" was a technical term that was explicated by hundreds of scholars.
Following the victory of the United States in the American Revolutionary War and the signing Treaty of Paris in 1783, the United States gained formal, if not actual, control of the British lands west of the Appalachians. Many thousands of settlers, typified by Daniel Boone, had already reached Kentucky and Tennessee and adjacent areas. Some areas, such as the Virginia Military District and the Connecticut Western Reserve (both in Ohio), were used by the states as rewards to veterans of the war. The issue of how to formally include these new frontier areas into the nation was an important issue in the Continental Congress of the 1780s and was partly resolved by the Northwest Ordinance (1787). The Southwest Territory saw a similar pattern of settlement pressure.
For the next century, the expansion of the nation into these areas, as well as the subsequently acquired Louisiana Purchase, Oregon Country, and Mexican Cession, attracted hundreds of thousands of settlers. The question of whether the Kansas frontier would become "slave" or "free" was a spark of the American Civil War. In general before 1860 Northern Democrats promoted easy land ownership and Whigs and Southern Democrats resisted. The Southerners resisted Homestead Acts because it supported the growth of a free farmer population that might oppose slavery.
When the Republican party came to power in 1860 they promoted a free land policy — notably the Homestead Act of 1862, coupled with railroad land grants that opened cheap (but not free) lands for settlers. In 1890, the frontier line had broken up (Census maps defined the frontier line as a line beyond which the population was under 2 persons per square mile).
The popular culture impact of the frontier was enormous, in dime novels, Wild West shows, and, after 1910, Western movies set on the frontier.
The American frontier was generally the most Western edge of settlement and typically more democratic and free-spirited in nature than the East because of its lack of social and political institutions. The idea that the frontier provided the core defining quality of the United States was elaborated by the great historian Frederick Jackson Turner, who built his Frontier Thesis in 1893 around this notion.
