Nickajack Dam is a hydroelectric dam in Marion County in the U.S. state of Tennessee. It is one of nine dams on the Tennessee River owned and operated by the Tennessee Valley Authority, which built the dam in the mid-1960s to replace the outdated Hales Bar Dam 6 miles (9.7 km) upstream. The dam impounds the 10,370-acre (4,200 ha) Nickajack Lake and feeds into Guntersville Lake. Nickajack Dam is named for a Cherokee village once located just upstream from the dam. The village was the namesake for Nickajack Cave, which was partially flooded by the reservoir.