Lai da Sontga Maria (Italian: Lago di Santa Maria) is a lake, located north of the Lukmanier Pass in Switzerland. It lies almost entirely in the municipality of Medel (canton of Graubünden), a tiny fraction of the south-west part of the lake belonging to the municipalities of Quinto and Blenio (canton of Ticino). The reservoir has a surface area is 1.77 km2 (0.68 sq mi). The arch dam Santa Maria was completed in 1968. The main road of the Lukmanier Pass runs along the eastern shore of the lake. In the lake, there is an anchor pylon of Lukmanier Powerline.