Devil's Well is a 0.1 mile lightly trafficked out and back trail located near Salem, Missouri that features a cave and is rated as moderate. The trail is primarily used for hiking and walking and is accessible year-round. Dogs are also able to use this trail but must be kept on leash.
dogs on leash
Devil's Well trail is a short walk to a spiral staircase descending down sinkhole leading to a view into an underground lake a hundred feet below the platform. This unusual "karst window" allows a look at the earth's plumbing. Devils Well was formed when the roof of a huge cavern, containing an underground lake, collapsed. The result was large sinkhole, with an opening in the bottom through which you can view the lake. The water level is about 100 feet below the platform, and the lake may be as much as 80 feet deep. (It can fluctuate 8 to 10 feet depending on the weather.)
My wife and I found this place quite a few years ago just driving around. It is a very neat place to see. You will need to bring a flashlight for sure if you want to see down into the cavern.
The walk is short, the stair case may be challenging for some. Take a flash light. Their is a light switch at the bottom to show the lake but sometimes it is burned out. Not remarkable, but fun. This is also the trailhead to the Cave Spring loop trail leading to a cave you can canoe back into. This cave is also were the underground lake exits into the Current River.