A mountain pass is a navigable route through a mountain range or over a ridge. Since many of the world's mountain ranges have presented formidable barriers to travel, passes have played a key role in trade, war, and both human and animal migration throughout history. At lower elevations it may be called a hill pass.
Mountain passes make use of a gap, saddle, col or notch. A topographic saddle is analogous to the mathematical concept of a saddle surface, with a saddle point marking the highest point between two valleys and the lowest point along a ridge.On a topographic map, passes are characterized by contour lines with an hourglass shape, which indicates a low spot between two higher points.
Passes are often found just above the source of a river, constituting a drainage divide. A pass may be very short, consisting of steep slopes to the top of the pass, or may be a valley many kilometres long, whose highest point might only be identifiable by surveying.
Roads have long been built through passes, as well as railways more recently. Some high and rugged passes may have tunnels bored underneath a nearby mountainside (like the Eisenhower Tunnel bypassing Loveland Pass in the Rockies) to allow faster traffic flow throughout the year.
The top of a pass is frequently the only flat ground in the area, and is a high vantage point. In some cases this makes it a preferred site for buildings. If a national border follows a mountain range, a pass over the mountains is typically on the border, and there may be a border control or customs station, and possibly a military post as well. For instance Argentina and Chile share the world's third-longest international border, 5,300 kilometres (3,300 mi) long. The border runs north–south along the Andes mountains, with a total of 42 mountain passes. On a road over a pass, it is customary to have a small roadside sign giving the name of the pass and its elevation above mean sea level.
As well as offering relatively easy travel between valleys, passes also provide a route between two mountain tops with a minimum of descent. As a result, it is common for tracks to meet at a pass; this often makes them convenient routes even when travelling between a summit and the valley floor. Passes traditionally were places for trade routes, communications, cultural exchange, military expeditions etc. A typical example is the Brenner pass in the Alps.
Some mountain passes above the tree line have problems with snow drift in the winter. This might be alleviated by building the road a few meters above the ground, which will make snow blow off the road.
There are many words for pass in the English-speaking world. In the United States, pass is very common in the West, the word gap is common in the southern Appalachians, notch in parts of New England, and saddle in northern Idaho.The term col, derived from Old French, is also used, particularly in Europe.
Scotland has the Gaelic term bealach (anglicised "balloch"), while Wales has the similar bwlch (both being British Celtic languages). In the Lake District of north-west England, the term hause is often used, although the term pass is also common—one distinction is that a pass can refer to a route, as well as the highest part thereof, while a hause is simply that highest part, often flattened somewhat into a high-level plateau.
There are thousands of named passes around the world, some of which are well-known, such as the Great St. Bernard Pass at 2,473 metres (8,114 ft) in the Alps, the Chang La at 5,360 metres (17,590 ft), and the Khardung La at 5,359 metres (17,582 ft) in Jammu and Kashmir, India. The roads at Mana Pass at 5,610 metres (18,410 ft) and Marsimik La at 5,582 metres (18,314 ft), on and near the China-India border respectively, appear to be world's two highest motorable passes. Khunjerab Pass between Pakistan and China at 4,693 metres (15,397 ft) is also a high-altitude motorable mountain pass. One of the famous but non-motorable mountain pass include Thorong La at 5,416 metres (17,769 ft) in Annapurna Conservation Area, Nepal.
Goat Fell is the highest point on the Isle of Arran. At 874 metres (2,866 ft), it is one of four Corbetts on the island. The mountain, along with nearby Brodick Castle, is now owned by the National Trust for Scotland.
The Little St Bernard Pass is a mountain pass in the Alps on the France–Italy border. Its saddle is at 2188 metres above sea level. It is located between Savoie, France, and Aosta Valley, Italy, to the south of the Mont Blanc Massif, exactly on the main alpine watershed. There is also a Great St. Bernard Pass, famous for giving the St Bernard breed its name, and a San Bernardino Pass.
The Cobbler is an 884 metres (2,900 ft) mountain located near the head of Loch Long in Scotland. It is a Corbett, and is an important site for rock climbing in the Southern Highlands. Many maps include the name Ben Arthur, but the name The Cobbler is more widely used.
Piz Bernina or Pizzo Bernina is the highest mountain in the Eastern Alps, the highest point of the Bernina Range, and the highest peak in the Rhaetian Alps. It rises 4,048.6 m and is located south of Pontresina and near the major Alpine resort of St. Moritz, in the Engadin valley with the massif partially in Italy. It is also the most easterly mountain higher than 4,000 m (13,000 ft) in the Alps, the highest point of the Swiss canton of Graubünden, and the fifth-most prominent peak in the Alps. The minor summit known as La Spedla is the highest point in the Italian Lombardy region.
Esk Pike is a fell in the English Lake District, one of the great cirque of hills forming the head of Eskdale.
Monte Rosa is a mountain massif located in the eastern part of the Pennine Alps. It is located between Italy and Switzerland (Valais). Monte Rosa is the second highest mountain in the Alps and western Europe, after Mont Blanc.
The Barre des Écrins is a mountain in the French Alps with a peak at 4102m altitude. It is the highest peak of the Massif des Écrins and the Dauphiné Alps and the most southerly alpine peak in Europe that is higher than 4,000 m. It is the only 4,000 m mountain in France that lies outside the Mont Blanc Massif. Before the annexation of Savoy in 1860 it was the highest mountain in France.
Grintovec is the highest mountain of the Kamnik–Savinja Alps, with an elevation of 2,558 metres (8,392 ft). It is a popular location for hiking, climbing and skiing. The first recorded ascent was in 1759 by the botanist Giovanni Antonio Scopoli.
Cime de la Bonette is a mountain in the French Alps, near the border with Italy. It is situated within the Mercantour National Park on the border of the departments of Alpes-Maritimes and Alpes-de-Haute-Provence, between the Ubaye Valley and the valley of the Tinée River.
In geomorphology, a col is the lowest point on a mountain ridge between two peaks. It may also be called a gap. Particularly rugged and forbidding cols in the terrain are usually referred to as notches. They are generally unsuitable as mountain passes, but are occasionally crossed by mule tracks or climbers' routes. The term col tends to be associated more with mountain rather than hill ranges.
Bimberi Peak or Mount Bimberi with an elevation of 1,913 metres (6,276 ft) located within the Brindabella Ranges is the highest mountain in the Australian Capital Territory (ACT). It is located on the border between New South Wales (NSW) and the ACT, the NSW portion in Kosciuszko National Park and the ACT portion in Namadgi National Park. It is accessible by bush walking trails and requires no specialised climbing skills, although there is no marked trail to the very summit.
The San Francisco Pass is a pass over the Andes mountains which connects Argentina and Chile. The highest point of this pass is at 4,726 m (15,505 ft) AMSL.
The Paso de Jama is a mountain pass through the Andes between Chile and Argentina, at an elevation of 4,200 m (13,800 ft) at the border.. It is the northernmost road border crossing between the two countries. The pass is reached via Chile Route 27 and via National Route 52 (Argentina). The Chile Route 27 reaches an altitude according to OpenStreetMap of 4,831 metres (15,850 ft) atin a roaddistance of 57.6 kilometres (35.8 mi) west of the border, making it one of the highest highways in Southamerica.
Route des Crêtes is an 89 km (55 mi) road in the Vosges Mountains in eastern France, which passes through the Parc Naturel Régional des Ballons des Vosges. It connects Sainte-Marie-aux-Mines (north) with Cernay (south) and runs on the border of the departements of Haut-Rhin (68) and Vosges (88). Most of the route is at an elevation in excess of 950 m (3,117 ft), with the highest point being at the Col du Grand Ballon. The road is generally open from April to November, but most of the route is closed in the winter by snow.
The saddle between two hills is the region surrounding the highest point of the lowest point on the line tracing the drainage divide connecting the peaks. When, and if, the saddle is navigable, even if only on foot, the saddle of a (optimal) pass between the two massifs, is the area generally found around the lowest route on which one could pass between the two summits, which includes that point which is a mathematically when graphed a relative high along one axis, and a relative low in the perpendicular axis, simultaneously; that point being by definition the col of the saddle.
The Agua Negra Pass is a pass over the Andes mountains which connects Argentina and Chile. The highest point of this pass is at 4,780 m (15,680 ft) AMSL.
The Pircas Negras Pass is a pass over the Andes mountains which connects Argentina and Chile. The border crossing between Argentina and Chile is at 4,164 m (13,661 ft) AMSL.
The Pichachén Pass is a pass over the Andes mountains that connects Argentina and Chile. The border crossing between Argentina and Chile is at 2,060 m (6,760 ft) AMSL.