Lake Okutama

Lake Okutama is a man-made reservoir in western Tokyo prefecture that stores water for the greater Tokyo area and sits within a mountainous, forested catchment. It is one of Tokyo’s principal water-supply reservoirs.

The lake is used for outdoor recreation and day trips from the Tokyo metropolitan area, with shoreline trails, viewpoints and boat or canoeing opportunities during warmer months. Several short hiking routes run along the surrounding ridges and there are picnic spots near the water.

The lake was created in the 20th century by damming the Tama River to secure water supply for Tokyo; the dam and reservoir have been operated to regulate river flows and supply needs. Over time access infrastructure and recreational facilities have been added while the reservoir continues to serve utility functions.

The reservoir lies in western Tokyo near the town of Okutama, set in steep, wooded terrain of the Okutama mountains. It is inside Tokyo prefecture rather than a distant prefecture, and is reached by rail from central Tokyo followed by a short road or foot transfer.

• Access: Terminus of the JR Ome Line at Okutama Station provides the most direct public-transport access; local buses and walking trails run from the station to lake viewpoints.

What to See #

• Ogōchi Dam: The concrete dam that formed the reservoir and provides water-supply regulation for the Tama River basin; viewing points at the dam offer panoramic lake and mountain views.