The Lago di Osiglia was created in the 1930s by damming a stretch of the upper Bormida di Millesimo for a hydroelectric scheme. The result is a long, narrow body of clear water set among wooded hillsides, with a small beach at the northern end where the village's summer life is concentrated.
The lake hosts regional canoeing championships and regattas through the summer, and trout fishing is allowed with a permit. The eastern shore has a path that follows the water for several kilometres and is one of the easier walks in the area, suitable for families.