The first settlers to the area were farmers, whose life was not easy as the land was very swampy and very difficult to reclaim. Farm animals that wondered off were often lost in the quicksands of the swamp, or fell prey to predators like foxes, bears and mountain lions. The swamps were infested with mosquitoes that brought yellow fever to the settlers.
The Pennsylvania legislature took action again in 1917, this time approving a $400,000 budget under the condition that the needed land in Ohio be purchased by the private sector. The Pymatuning Land Company was formed and raised the funds to purchase the needed Ohio properties. The land was finally acquired in full by 1931 when Governor Gifford Pinchot approved $1.5 million to complete the dam. 7,000 men began work on the dam in 1931 and the project was completed in 1934, with a final total cost of $3,717,739. The lake now holds 64.3 billion gallons (243.3 million m³) of water, covering 17,088 acres (69.15 km²) over a length of 17 miles (27 km) with a width of 1.6 miles (2.6 km) at the widest and 70 miles (113 km) of shoreline with a maximum depth of 35 feet (11 m). The lake has served to provide a water supply for the Shenango and Beaver valleys, it has lessened the damage caused by floods, and provided recreation for the people of Ohio and Pennsylvania. Two state parks, each named "Pymatuning State Park", are on the lake in Ohio and Pennsylvania.