Bellagio is a comune (municipality) in the Province of Como in the Italian region of Lombardy. It is located on Lake Como, also known by its Latin-derived name Lario, whose arms form an inverted Y. The triangular land mass at the base of the inverted Y is the Larian Triangle: at its northern point sits Bellagio, looking across to the northern arm of the lake and, behind it, the Alps. It has always been famous for its location. It belongs to a mountain community named Comunità montana del Triangolo lariano (Larian Triangle mountain community), with base in Canzo.

Bellagio is situated upon the cape of the land mass that divides Lake Como in two. The city centre occupies the tip of the promontory, while other districts are scattered along the lake shores and up the slopes of the hills. The great Pleistocene glaciations with their imposing flows coming from the Valtellina and Valchiavenna modelled the actual landscape of Lake Como: at least four times the glaciers went as far as Brianza to the south. From the ancient glacial blanket only the highest tops emerged, one of them Mount St. Primo, which obliged the glaciers to divide into two arms.

Nowadays, a luxuriance of trees and flowers is favoured by a mild and sweet climate. The average daytime temperature is mitigated during the afternoon by the characteristic breva, the gentle breeze of Lake Como.