Basically, Turner held that American democracy was shaped by the frontier, namely by the contest of the settler with the wilderness of the frontier. There the settler learned self-reliance, judged others by their abilities, strove to improve his or her lot, and grew distrustful of external authority and formal institutions. In short, the frontier molded an American national character that was individualistic and egalitarian. Turner's work stimulated a tremendous amount of research and writing on the history and meaning of the frontier.
There is no question that the process of peopling the West is a central theme in U.S. history, although not, perhaps, for the reasons Turner suggested. The cultivation of frontier lands provided food for the growing number of workers in Eastern cities; its mineral wealth and other natural resources aided industrialization; and the need to keep the East and West united led to a complex and efficient national system of transportation and communication. At the same time, the existence of barely settled lands helped preserve a rural tinge to America well into the 20th cent. Many studies have been devoted to the fur trade frontier, the mining frontier, the grazing frontier, and other types of frontier, but emphasis has been to a large extent on the solid achievements of the farming frontier and on the central United States.
See F. J. Turner, The Frontier in American History (1920); F. L. Paxson, History of the American Frontier (1924); W. P. Webb, The Great Plains (1931) and The Great Frontier (1952); R. A. Billington and J. B. Hedges, Westward Expansion (1949); H. N. Smith, Virgin Land (1950); L. B. Wright, Culture on the Moving Frontier (1955); R. A. Bartlett, Great Surveys of the American West (1980); R. V. Hine, Community on the American Frontier (1985); P. M. Nelson, After the West Was Won (1989).
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.
In the earliest days of European settlement of the Atlantic coast, the frontier was essentially any part of the forested interior of the continent beyond the fringe of existing settlements along the coast and the great rivers, such as the St. Lawrence, Connecticut, Hudson, Delaware, Susquehanna River and James.
English, French, Spanish and Dutch patterns of expansion and settlement were quite different. Only a few thousand French migrated to Canada; these habitants settled in villages along the St. Lawrence river, building communities that remained stable for long stretches; they did not leapfrog west the way the Americans did. Although French fur traders ranged widely through the Great Lakes and Mississippi River watershed, as far as the Rocky Mountains, they did not usually settle down. Actual French settlement in these areas was limited to a few very small villages on the lower Mississippi and in the Illinois Country. Likewise, the Dutch set up fur trading posts in the Hudson river valley, followed by large grants of land to patroons who brought in tenant farmers who created compact, permanent villages. They did not push westward.
In contrast, the English colonies generally pursued a more systematic policy of widespread settlement of the New World for cultivation and exploitation of the land, a practice that required the extension of European property rights to the new continent. The typical English settlements were quite compact and small--under a square mile. Conflict with the Native Americans arose out of political issues, viz. who would rule. Early frontier areas east of the Appalachian Mountains included the Connecticut river valley. The French and Indian Wars of the 1760s resulted in a complete victory for the British, who took over the French colonial territory west of the Appalachians to the Mississippi River. Americans began moving across the Appalachians into areas such the Ohio Country and the New River Valley.
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 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.
A Canadian frontier thesis was developed by Canadian historians Harold Adams Innis and J. M. S. Careless. They emphasized the relationship between the center and periphery. Katerberg argues that "in Canada the imagined West must be understood in relation to the mythic power of the North." [Katerberg 2003] In Innis's 1930 work The Fur Trade in Canada, he expounded on what became known as the Laurentian thesis: that the most creative and major developments in Canadian history occurred in the metropolitan centers of central Canada and that the civilization of North America is the civilization of Europe. Innis considered place as critical in the development of the Canadian West and wrote of the importance of metropolitan areas, settlements, and indigenous people in the creation of markets. Turner and Innis continue to exert influence over the historiography of the American and Canadian Wests. The Quebec frontier showed little of the individualism or democracy that Turner ascribed to the American zone to the south. The Nova Scotia and Ontario frontiers were rather more democratic than the rest of Canada, but whether that was caused by the need to be self-reliant on the frontier itself or the presence of large numbers of American immigrants is debated.
The Canadian political thinker Charles Blattberg has argued that such events ought to be seen as part of a process in which Canadians advanced a "border"-- as distinct from a "frontier"--from east to west. According to Blattberg, a border assumes a significantly sharper contrast between the civilized and the uncivilized since, unlike with a frontier process, the civilizing force is not supposed to be shaped by that which it is civilizing. Blattberg criticizes both the frontier and border "civilizing" processes.