The dam is made of earth and concrete,[5] supplemented by three saddle dikes,[1] and was built to provide a water source for the Atlanta area, power homes, and prevent flooding of the Chattahoochee River.

[5] During the construction of the dam, Johnnie Callahan died during a rockslide when cutting an intake tunnel into the face of the granite rock wall.

[11] On February 1, 1956, the dam was completed when the sluice gates were closed and Lake Lanier began to fill.

[9] The power plant went into full-scale operation in July 1958,[13] and the lake reached its intended level on August 1 of that year.

[17] Because the earthen slopes on the outer side of the dam exceed 40% grade (21.8°, 1 in 2.5) and contain rocks and drop off points, they are too steep and unsafe to practically maintain by a landscaping crew.

[18] To address this, the US Army Corps of Engineers use goats to maintain the grass and vegetation on the slope[9] as it is more economically viable than alternatives.