Lyons Reservoir is a man-made lake that is formed by Lyons Dam that was constructed back in 1930 by PG&E. This reservoir is currently the municipal water supply for Twain Harte and other localities in the lower elevations of the Sierra Nevada above Sonora. Lyons Reservoir is surrounded by the Stanislaus National Forest and provides many recreational opportunities like fishing, hiking, biking, horse back riding, picnicking, bird watching among others. Since Lyons is a municipal water supply there is no swimming allowed. Lyons Reservoir sits at 4200 feet elevation, and as a result is only open from May 1 to November 1, where outside of those months the main gate at hwy 108 is locked and no entry is allowed. The opening day and closing day may vary depending on the weather at that time of the year. Visit the Stanislaus National Forest website for area status.
Several hikes near Lyons Reservoir include the Sugar Pine Railroad Grade from Confidence to Lyons, the Sugar Pine Railroad Grade from Lyons to Fraser Flat and the Lyons Lake Loop. All these hikes are relatively flat and are doable by almost anyone, however, the Lyons Lake Loop requires you to wade through the S. Fork Stanislaus at the north end of the lake.
Fishing is also a very popular activity at Lyons Reservoir where on any given day you will find several fishermen casting their lines off the dam. California fishing regulations apply so make sure you are in compliance.
Lyons Reservoir is off Hwy 108 a couple of miles north-east of Mi-Wuk Village. A two-mile dirt road takes you down to a parking area near the lake. The dirt road, although bumpy, is maintained and passable by most vehicles.