frontier, in U.S. history, the border area of settlement of Europeans and their descendants; it was vital in the conquest of the land between the Atlantic and the Pacific. The importance of the westward movement of the population and the lure of the frontier were clear even to colonial writers and early U.S. historians, but the theory that the frontier was a governing factor (if not the governing factor) in developing a distinctive U.S. civilization was not formulated until 1893, when Frederick Jackson Turner presented his thesis.

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.

North-West Frontier Province, province and historic region (1998 pop. 17,554,674), c.41,000 sq mi (106,200 sq km), NW Pakistan, bounded on the N and W by Afghanistan. Peshawar is the capital. An area of high, barren mountains dissected by fertile valleys, it is predominantly agricultural. Wheat is the chief crop; barley, sugarcane, tobacco, cotton, and fruit trees are also cultivated, and livestock is raised. Irrigation works, notably the Warsak project on the Kabul River, supplement the scanty rainfall. Mineral resources include marble, rock salt, gypsum, and limestone. There are some mountain forests. Food processing, cotton and wool milling, papermaking, and the production of cigarettes, textiles, chemicals, and fertilizer are the main industries; handicrafts also flourish. Some Pathan tribes inhabit the province in the plains and lower hills.

The region has been historically and strategically important due to passes leading into India, through which came invaders from central Asia. Alexander the Great conquered the region c.326 B.C., but his garrisons were unable to hold the region. In the early centuries A.D., Kanishka and his Kushan dynasty ruled the area. The Pathans arrived in the 7th cent., and by the 10th cent. conquerors from Afghanistan had made Islam the dominant religion. Under local Pathan rule from the late 12th cent. until Babur annexed it to his Mughal empire, the region paid nominal allegiance to the Mughals in the 16th and 17th cent. After Nadir Shah's invasion (1738), it became a feudatory of the Afghan Durrani kingdom. The Sikhs later held the area, which passed to Great Britain in 1849. The British maintained large military forces and paid heavy subsidies to pacify the Pathan resistance.

Britain separated the region from the Punjab of India in 1901 and constituted the North-West Frontier Province, whose people voted to join newly independent Pakistan in 1947. Following the absorption of the North-West Frontier Province into Pakistan, neighboring Afghanistan engendered the Pushtunistan Controversy (see Afghanistan). From 1955 to 1970 the North-West Frontier Province was a section of the consolidated province of West Pakistan. In 1970, the region was once again granted provincial status.

The Soviet invasion of Afghanistan caused over 3 million refugees to flee to the North-West Frontier Province. Peshawar became the military and political center of the Afghan anti-Soviet coalition. The Soviet withdrawal in 1989 raised hopes that the refugees would be repatriated. Although renewed factional fighting in 1992 threatened the process, all Afghan tented refugee camps were closed by 1995.

North-East Frontier Agency, India: see Arunachal Pradesh.