The O'Shaughnessy Dam is located on the Scioto River near Dublin, Ohio, United States. The dam forms O'Shaughnessy Reservoir, which is a major source of drinking water for the city of Columbus. It was completed in 1925 following recommendations of then superintendent Jerry O'Shaughnessy (for whom the dam was named). At the time, the reservoir was described as "the finest inland waterway in the United States." Located 10 miles (16 km) upstream of the smaller Griggs Dam, it provides a large area for various forms of recreation in addition to its water supply duties. The reservoir holds 6.3 billion US gallons (24,000,000 m³) over a surface area of 845 acres (3.42 km²).