Visit a Cave
If you see this state park from an airplane, it's not that impressive. You can see similar limestone bluffs along the Meramec River and wooded hillsides across the state. But the crown jewel of this state park is its namesake, Onondaga Cave.
It's one of the premier caves in the state, and that's quite a distinction. Because, with more than 5,000 caves, Missouri is known as "the cave state." Tours start at the visitor center, before descending into the cavern. About 40,000 people visit the cave each year, anxioux to see features like stalagmites and draperies.
"Right now, we are 80 feet below the surface," explained one of the tour guides. "What we're walking over right now is the Lost River. It's our main stream that runs through the cave."
Dripping water created this underground treasure chest of formations, such as soda straws. Water trickles down through the middle, leaving minerals and often plugging the bottom of the straw. Water on the outside of the formation thickens to form stalactites. Then, soda straws and stalactites drip onto the ground where minerals build up and form stalagmites. And, sharp-eyed visitors may also spot some of the cave's other features.
"We have a little bat there, a little pipestrell. He's the most common type of bat here in Missouri. He's got a little dew on him right now. Yeah, he's just hangin out," the tour guide pointed out. "The water has been pretty high this year because we've had such a wet winter and these fill only by drip water, there is actually no water flowing in here. It just fills up by all these formations dripping into here very slowly."
Impressive formations that include the Lillypad Room, Queen's Canopy and Twin Towers.
Daily tours take place throughout the summer. They cost $10 for adults, and $5 for children 6 to 12 years old.