Lagginhorn, Summit in the Pennine Alps, Switzerland

Lagginhorn is a mountain summit in the Pennine Alps in Switzerland, just above 4,010 meters (13,156 feet), and one of the recognized 4,000-meter peaks of the Alps. The route to the top crosses loose scree fields and short rock passages that require basic scrambling ability.

The Lagginhorn was first climbed in 1856 by local guides alongside a British mountaineer. In the decades that followed, it became a regular destination for alpinists exploring the high peaks of Valais.

Locals in the Saastal call the mountain ts Lagg'ii, and the name Lagginhorn may come from the Latin lacus or the Arabic allâqîn. On the first ascent in 1856, the Saas-Grund curate Johann Josef Imseng climbed in his clerical robes, which Edward Levi Ames called his "peculiar garb".

The usual start is Saas-Grund (1560 m), from where trails lead to the Weissmies Hut (2726 m); the Hohsaas cable car reaches Kreuzboden (2398 m) or the Hohsaas Hut (3101 m). The normal route is graded PD (I–II) and is mostly rock, but the Swiss Alpine Club warns that fatal accidents occur every year on the descent. Between 2009 and 2021 eleven rockfalls were recorded.

Unlike most 4,000-meter summits in the Alps, the Lagginhorn can be climbed without crampons when conditions are snow-free. This makes it one of the few high summits that climbers with limited alpine experience can realistically aim for.