The reservoir was named for Charles W. McConaughy, a grain merchant and mayor of Holdrege, Nebraska, one of the leading promoters of the project.

The lake, formed by Kingsley Dam, is a man-made body of water that is 22 miles (35 km) long, 4 miles (6.4 km) wide at its largest point, and 142 feet (43 m) deep near the dam (at full capacity) – it was constructed between 1936 and 1941 and is fed by the North Platte River.

Return flows from these projects to the North Platte River make up a significant portion of the inflows to Lake McConaughy.

The dam was named for George P. Kingsley, a Minden, Nebraska banker, who worked with C. W. McConaughy to promote the project.

The dam's face is protected by more than a million tons of rock in several layers and more than 180,000 "jackstones," (rebar-reinforced concrete tetrahedrons), each weighing 800 lb (360 kg).