They are located in Italy (the Aosta Valley and Piedmont) and Switzerland (Valais).

[1] The Italian side is drained by the rivers Dora Baltea, Sesia and Toce, tributaries of the Po.

The main chain (watershed between the Mediterranean Sea and the Adriatic Sea) runs from west to east on the border between Italy (south) and Switzerland (north).

Unlike many other mountain ranges, the higher peaks are often located outside the main chain and found themselves between the northern valleys (Grand Combin, Weisshorn, Mischabel, Weissmies).

The chief peaks of the Pennine Alps are: Main glaciers: The chief passes of the Pennine Alps are:[2] Some regional nature parks, like the Parco Naturale Alta Valsesia (6,511 ha - Piedmont, IT),[4] the Riserva Naturale Mont Mars (390 ha - Aosta Valley, IT) [5] and the Regional park of Binn valley (15,891 ha - Valais, CH),[6] have been established on both sides of the main water divide.