Upper San Leandro Reservoir, body of water

The Upper San Leandro Reservoir is a large man-made lake in California that provides drinking water for nearby communities and is held back by an earth-filled dam. A walking trail circles the water, offering views of the lake surface, surrounding hills, and vegetation where visitors can stroll and explore the quiet landscape.

The reservoir was originally built in 1926 with a smaller dam that flooded a valley previously home to small communities. A new, larger dam was constructed in 1977 that stands 182 feet tall and holds significantly more water to provide the region with safer and more reliable water storage.

The reservoir serves as a walking destination where the community connects with nature while the water remains protected for public use. Its role as an accessible outdoor space reflects a balance between conservation and allowing people to experience the landscape firsthand.

When walking the trails, wear comfortable shoes and bring water, especially if you plan to walk the full loop. Parking areas and nearby parks make visiting straightforward, but with no facilities directly at the reservoir, it helps to bring any supplies you might need.

The reservoir and its feeder streams hold a population of landlocked rainbow trout, cut off from San Francisco Bay by the dam. The reservoir is closed to boating and fishing to protect water quality, so the fish remain undisturbed; a public trail system around the lake is the only access.