Fort Loudoun Lake is a reservoir in east Tennessee on the upper Tennessee River, extending about 50 miles (80 km) along the river upstream from Fort Loudoun Dam, at Lenoir City, to Knoxville.

The fort was named for John Campbell, the fourth Earl of Loudoun, commander of British forces in North America at the time.

[1] Fort Loudoun is a popular recreation destination, known for bass fishing, boating, and birdwatching.

The tailwater area immediately below the dam is an excellent site for viewing a variety of waterbirds, including herons, cormorants, gulls, osprey, and bald eagles.

Barges passing through the Fort Loudoun lock carry about half a million tons of cargo a year.