Lake Okutama (奥多摩湖, Okutama-ko) is in Tokyo and Yamanashi Prefectures in Japan. Lying above the Ogōchi Dam, it is also known as the Ogōchi Reservoir. The lake occupies part of the town of Okutama in Nishitama District, Tokyo and the village of Tabayama in Kitatsuru District, Yamanashi. Lake Okutama is an important source of drinking water for Tokyo.

Data

• Dam height: 149 m
• Dam length: 353 m
• Greatest depth: 142 m
• Circumference when full: 45.37 km
• Altitude of surface when full: 526.5 m
• Area of surface when full: 4.25 km²
• Capacity: 185 400 000 m³
• Completion: 1957
• Displaced: 945 households, 6000 people
• Died during construction: 87 people

Around the lake

The Taba (Tama) River feeds Lake Okutama at its western end. From the southwest, the Kosuge River also flows into the lake. The Tama River drains the lake at the eastern end.

The surroundings are famous for cherry blossoms in the spring.