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, which is to the north of the lake, was completed in 1968. The main road of the Lukmanier Pass runs along the eastern shore of the lake.

Lai da Sontga Maria
Looking towards the Gannaretsch range from near the pass
Lai da Sontga Maria Show map of Canton of Graubünden Lai da Sontga Maria Show map of Canton of Ticino Lai da Sontga Maria Show map of Switzerland Lai da Sontga Maria Show map of Alps
Location	Graubünden/Ticino, Switzerland
Coordinates	46°34′30″N 8°47′45″E / 46.57500°N 8.79583°E / 46.57500; 8.79583
Type	reservoir
Primary inflows	Reno di Medel, Murinascia Grande, various creeks
Primary outflows	Froda
Catchment area	27.1 km2 (10.5 sq mi)
Basin countries	Switzerland
Surface area	1.77 km2 (0.68 sq mi)
Max. depth	86 m (282 ft)
Surface elevation	1,908 m (6,260 ft)

The lake lies at a height of 1,908 metres above sea level and is surrounded by mountains over 3,000 metres on both sides. The highest peak overlooking Lai da Sontga Maria is the Scopi (3,190 m), on the east side. On the west side are Piz Gannaretsch (3,040 m) and Piz Rondadura (3,016 m). On the south side (in Ticino), the lake is overlooked by Pizzo dell'Uomo (2,663 m). The lake is drained by the Rein da Medel, a tributary of the Anterior Rhine.^[1]

In the lake, there is an anchor pylon of Lukmanier Powerline.