Nickajack Lake stretches northeast for over 46 miles (74 km), all the way to the base of Chickamauga Dam in Chattanooga.

The dam's original design allowed for an 800-by-110-foot (244 by 34 m) main lock beside the auxiliary, but it was never completed.

[1] In 1939, after a contentious court battle, TEPCO was forced to sell its assets— including Hales Bar Dam— to the Tennessee Valley Authority.

Around the same time, TVA began expanding locks on its dams to at least 600 feet (180 m) to accommodate the increase in traffic the river had experienced since World War II, and it was determined that expanding the Hales Bar lock would be "prohibitively" expensive.

Rather than spend the necessary expenses to upgrade Hales Bar, a decision was made in 1963 to build a new dam altogether on a more solid bedrock a few miles downstream.

[1] The Nickajack Dam project was authorized January 9, 1964, and construction began April 1, 1964.

Funding set aside for repair work on Hales Bar was transferred to the Nickajack project.