Like High Falls, Onion Falls is featured in the 1938 publication Scenic Resources of the Tennessee Valley, which calls it “a good example of a waterslide, about 100 feet in height.” According to the book, it is also called Engrons Falls, engron being the local word for the wild onion. The name probably came from the shape of the falls—a slide over a rounded rockface.
The real Onion Falls no longer exists. It was located a short distance west of the current Lake Glenville dam. When the dam was built in 1941, it blocked the natural course of the river, and a new channel was blasted out of the rock below the dam outtake. You can see the new channel as you drive across the dam.
Unfortunately, I haven’t been able to find any photos of Onion Falls before the dam. But I do have a 1935 map verifying that Onion Falls was lost under the talus slope of the dam. Interestingly, the 1946 Glenville topo has the new channel labeled as Onion Falls. I guess the mapmakers assumed that the manmade waterfall was the real Onion Falls. Had they reviewed earlier maps, they would have known that assumption was incorrect.
Despite the fact that it isn’t a real falls, the outflow waterfall from the dam is one heck of an impressive sight during a dam release. Unfortunately, Duke Energy prohibits anyone from climbing down the slope to view it from the base or from entering the channel above the falls. All the photos on this page were made in the off-limits area. You must have special permission from Duke Energy to view the waterfall from these vantage points. But there is one decent vantage point that’s open to the public. Access is from the wide pullout on the right side of the road 0.2 mile west of the dam. It’s about halfway between the dam and the High Falls trailhead.