Terminology[edit]
A khulan (Mongolian wild ass) on a hill in the Gobi of Mongolia at sunset
Chocolate Hills of the Philippines
Hills in Tuscany, Italy
The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally considered to be less tall and less steep than a mountain. In the United Kingdom, geographers historically regarded mountains as hills greater than 1,000 feet (300 m) above sea level, which formed the basis of the plot of the 1995 film The Englishman Who Went Up a Hill But Came Down a Mountain. In contrast, hillwalkers have tended to regard mountains as peaks 2,000 feet (610 m) above sea level: the Oxford English Dictionary also suggests a limit of 2,000 feet (610 m) and Whittow[1] states "Some authorities regard eminences above 600 m (2,000 ft) as mountains, those below being referred to as hills." The Great Soviet Encyclopedia defines hill as an upland with a relative height up to 200 m (660 ft).[2]
Today, a mountain is usually defined in the UK and Ireland as any summit at least 2,000 feet (or 610 meters) high,[3][4][5][6][7] while the official UK government's definition of a mountain is a summit of 600 meters or higher.[8] Some definitions include a topographical prominence requirement, typically 100 feet (30 m) or 500 feet (152 m).[5] In practice, mountains in Scotland are frequently referred to as "hills" no matter what their height, as reflected in names such as the Cuillin Hills and the Torridon Hills. In Wales, the distinction is more a term of land use and appearance and has nothing to do with height. For a while, the U.S. defined a mountain as being 1,000 feet (304.8 m) or more tall. Any similar landform lower than this height was considered a hill. The United States Geological Survey (USGS), however, has concluded that these terms do not in fact have technical definitions in the U.S.[9]
A hillock is a small hill. Other words include knoll and (in Scotland, Northern Ireland and northern England) its variant, knowe.[10] Artificial hills may be referred to by a variety of technical names, including mound and tumulus.
Hills of the Judean Desert
Hills may form through geomorphic phenomena: faulting, erosion of larger landforms, such as mountains and movement and deposition of sediment by glaciers (e.g. moraines and drumlins or by erosion exposing solid rock which then weathers down into a hill.) The rounded peaks of hills results from the diffusive movement of soil and regolith covering the hill, a process known as downhill creep.
Various names used to describe types of hill, based on appearance and method of formation. Many such names originated in one geographical region to describe a type of hill formation peculiar to that region, though the names are often adopted by geologists and used in a wider geographical context. These include:
Drumlin – an elongated whale-shaped hill formed by glacial action.
Butte – an isolated hill with steep sides and a small flat top, formed by weathering.
Kuppe – a rounded hill or low mountain, typical of central Europe
Tor – a rock formation found on a hilltop; also used to refer to the hill, especially in South West England.
Puy – used especially in the Auvergne, France, to describe a conical volcanic hill.
Pingo – a mound of earth-covered ice found in the Arctic and Antarctica.
