About this spot
Reached via the Rainbow Lake Trail on Signal Mountain, this small falls and plunge pool is locally known as Signal Mountain Blue Hole -- one of the most-visited swimming holes in the Chattanooga area. The water is clear near the rocky edges, where people jump from boulders around the pool at their own risk. Depth drops off fast: shallow at the rim but reportedly much deeper mid-pool with an unknown bottom, so several local guides warn against diving headfirst. The OSM tag 'Mystery Falls' at this exact point is unrelated to a separate, much larger cave-bound waterfall of the same name near Lookout Mountain -- don't confuse the two. There's no fee, but also no lifeguard, signage, or barriers at the pool.
Safety first. Cliff jumping is inherently dangerous and can cause serious injury or death. Conditions — water depth, submerged hazards, and access — change constantly. CliffScout is community-sourced reference information, not a guarantee a spot is safe. Always assess the conditions yourself before jumping, and never jump where you're unsure. You assume all risk.