International Climbing and Mountaineering Federation in the context of "Mountaineer"

Mountaineering, mountain climbing, or alpinism is a set of outdoor activities that involves ascending mountains. Mountaineering-related activities include traditional outdoor climbing, skiing, and traversing via ferratas that have become sports in their own right. Indoor climbing, sport climbing, and bouldering are also considered variants of mountaineering by some, but are part of a wide group of mountain sports.

Unlike most sports, mountaineering lacks widely applied formal rules, regulations, and governance; mountaineers adhere to a large variety of techniques and philosophies (including grading and guidebooks) when climbing mountains. Numerous local alpine clubs support mountaineers by hosting resources and social activities. A federation of alpine clubs, the International Climbing and Mountaineering Federation (UIAA), is the International Olympic Committee-recognized world organization for mountaineering and climbing. The consequences of mountaineering on the natural environment can be seen in terms of individual components of the environment (land relief, soil, vegetation, fauna, and landscape) and the location/zone of mountaineering activity (hiking, trekking, or climbing zone). Mountaineering impacts communities on economic, political, social, and cultural levels, often leading to changes in people's worldviews influenced by globalization, specifically foreign cultures and lifestyles.

This list tabulates all of the 82 official mountain summits of 4,000 metres (13,123 ft) or more in height in the Alps, as defined by the International Climbing and Mountaineering Federation (UIAA). They are the highest mountains of the Alps, all located in Switzerland (48), Italy (38), and France (25), and are often referred to by mountaineers as the Alpine four-thousanders. A further table of 46 subsidiary mountain points which did not meet the UIAA's selection criteria is also included.

The official UIAA list of 82 mountain summits, titled in English as 'The 4000ers of the Alps' was first published in 1994. They were selected primarily on a prominence of at least 30 metres (98 ft)) above the highest adjacent col or pass. Additional criteria were used to include or exclude some points, based on the mountain's overall morphology and mountaineering significance. (For example, the Grand Gendarme on the Weisshorn was excluded, despite meeting the prominence criterion as it was simply deemed part of that mountain's ridge.) A further 46 additional points of mountaineering significance, such as Pic Eccles, which did not meet the UIAA's primary selection criteria, were then included within an 'enlarged list'. Another, less formal, list of 4000 metre alpine mountains, containing only independent peaks with a prominence of over 100m, and based on an earlier 1990s publications by Richard Goedeke, contains just 51 mountains.

This is a list of the highest mountains of Switzerland. This list only includes summits above 3,600 metres (11,811 ft) with a topographic prominence of at least 30 metres. Note that this list includes many secondary summits that are typically not considered mountains (in the strict sense of the term) but that are mainly of climbing interest. For a list of major summits only, without elevation cut-off, see List of mountains of Switzerland.

The International Climbing and Mountaineering Federation defines a summit in the Alps as independent, if the connecting ridge between it and a higher summit drops at least 30 m (a prominence/drop of 30 m, with the lowest point referred to as the "key col"). There are over 350 such summits exceeding 3,600 m in Switzerland, all located in the High Alps, in five cantons: Valais, Bern, Graubünden, Uri, and Glarus. All mountain heights and prominences on the list are from the largest-scale maps available.

In these lists of mountains in Ireland, those within Northern Ireland, or on the Republic of Ireland – United Kingdom border, are marked with an asterisk, while the rest are within the Republic of Ireland. Where mountains are ranked by height, the definition of the topographical prominence used to classify the mountain (e.g. the change in elevation required between neighbouring mountains), is noted. In British definitions, a height of 600 metres (1,969 ft) is required for a mountain, whereas in Ireland, a lower threshold of 500 metres (1,640 ft) is sometimes advocated.

The lowest minimum prominence threshold of any definition of an Irish mountain is 15 metres (49 ft) (e.g. the Vandeleur-Lynam), however most definitions, including the International Climbing and Mountaineering Federation (UIAA) criteria, do not consider prominences below 30 metres (98 ft) as being mountains (e.g. must at least be an Arderin or a Hewitt). Many British definitions consider a peak with a prominence below 150 metres (492 ft), as being a top, and not a mountain (e.g. must be a Marilyn). A widely used definition of an Irish mountain requires a minimum prominence of 100 metres (328 ft) (e.g. a HuMP), and is the basis for the 100 Highest Irish Mountains.