Bacino di San Giacomo, Twin reservoirs in Valdidentro, Italy.

Bacino di San Giacomo is a reservoir in the Lombardy Alps that forms one of two large water bodies within Stelvio National Park alongside the Cancano reservoir. Both sit at approximately 1907 meters elevation in an alpine valley with steep, rocky shores.

Construction of these reservoirs began in the 1920s, with the San Giacomo dam completed in the 1940s and the Cancano dam finished later. This was a major hydroelectric power project for the region.

The submerged village of San Giacomo with its medieval church lies hidden beneath the water today. This lost settlement was once a center for iron mining activity in the area.

The access road features many hairpin bends and is often subject to driving restrictions during summer months. Visitors should check current road conditions beforehand and start early, as the route is narrow and winding.

The two basins that make up the Cancano lakes have different names despite lying side by side: Lago di San Giacomo and Lago di Cancano II. Together they hold 187 million cubic metres of water, fed by the Adda and by the Spöl, Gavia-Forni-Braulio and Viola Bormina canals.