Lago Ritom is a lake in the Piora valley, Ticino, Switzerland.

The natural lake is used as a reservoir by the Swiss Federal Railways (SBB-CFF-FFS) to generate hydro-electric power for the Gotthard line.

The first dam was built in 1918 and, in 1950, its height was increased by 23 m. The lake's surface area is 1.49 km² at an elevation of 1850 m. With Lake Cadagno and Lago di Tom, it is one of the main lakes in the Piora valley.

The track with a length of 1,369 m has a maximum inclination of 87.8%,[1] the highest in Europe after the Gelmerbahn funicular (106%).

This article related to a lake in Ticino is a stub.