Lake Eufaula, sometimes referred to as Eufaula Lake, is a reservoir in Oklahoma. It is located on the Canadian River, upstream from its confluence with the Arkansas River and near the town of Eufaula. The lake covers parts of McIntosh County, Pittsburg, Haskell and Okmulgee counties and drains . Water sources include the Canadian, North Fork Canadian and Deep Fork rivers. It is the largest-capacity lake in the state of Oklahoma with a volume of , a surface area of and of shoreline. History Congress approved construction of the dam and lake in 1946 to provide flood control, hydroelectric power, water supply, navigation and recreation. The U. S. Army Corps of Engineers began construction of the 975 meter-long (3,199 feet) Eufaula Dam wall in 1956 and was completed in 1964. President Lyndon B. Johnson came to Oklahoma to dedicate the dam on September 25, 1964. The dam holds back a lake area of over . The hydroelectric power station was designed to provide 90,000 kilowatts of electric power from the lake waters. According to the Corps of Engineers in 2015, the Eufaula project cost $121.4 million, and has prevented nearly $575.5 million in flood damages since its completion. The lake attracts about 2.5 million visitors every year. Heavy rains in the spring of 2015 caused Lake Eufaula to rise so rapidly that the Corps of Engineers opened the flood gates and released water at rates as high as per second. This was the highest rate since 1990. Dam construction Eufaula Dam is east of the city of Eufaula, Oklahoma. It is long and high. It is constructed with an earthen embankment and concrete. The associated hydroelectric power plant has three turbines, each rated at 30 megawatts, for a total installed capacity of 90 megawatts The dam was approved by the Rivers and Harbors Act of 1946 and construction began in 1956. In February 1964, the river was closed and the generators went operational in September 1964. State Highway 71 runs across the top of the dam. Recreational facilities Activities at Lake Eufaula include boating, fishing, swimming, hiking, hunting, golfing and horseback riding. Picnic areas are scattered throughout the area. Facilities include marinas, boat ramps, swim beaches, tent and RV campsites, cabins, group shelters, restrooms, showers and an enclosed fishing dock. These can be found at Lake Eufaula State Park and the physically-separate Arrowhead Area at Lake Eufaula State Park. A