A water-filled sinkhole in the Mark Twain National Forest, left when a cave roof collapsed; locals call it the Blue Hole for its deep blue-green water. The opening is about 20 feet wide, 100 feet long, and 50 feet down to the water, which is 140 to 220 feet deep and connects to at least 2,100 feet of flooded cave. An easy path circles the rim, but the way down is steep. Swimming, wading, and diving are prohibited.
- Where
- Blue Hole Rd off Hwy 49, near Mill Spring, MO
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