I came into this spot blind last night just looking for a place to sleep. Randomly winding up at Big Spring in Missouri just searching for a campsite? Pretty fortunate. I broke camp and drove just a short distance outside the campground to find Big Spring but you could walk/hike the Slough Trail if you are so inclined (though I didn’t know at the time). Map at the trailhead gives a better picture of the area.
At the parking lot nearest Big Spring it’s only a short walk down a stone path to reach the water.
Your first view of the spring is only steps off the pavement. My first thought was “that’s a spring?!” It looks more like a small rapids or maybe a waterfall coming out of the cliff side. The waters are an amazing deep shade of turquoise blue and green, it almost doesn’t look real.
Here’s a more zoomed in view to give additional detail. I don’t think I’ve ever seen anything like it, usually back home most springs start as a puddle or small stream but nothing that even compares to this one.
Continuing to follow the stone path will lead you to the very top of the spring. There are quite a few people here today – I think some kind of nature event is going on – but not a big deal. Summer months I can imagine this would be a very busy destination.
Near the rocky cliff there is a great sign detailing karst topography and how the spring forms. In a nutshell, draining rainwater becomes slightly acidic, and as it filters through the ground and rock it dissolves the dolomite and other minerals creating networks of underground caves and tunnels. When the water re-emerges from those drainages it becomes a spring. Notice the entire state of Missouri on the map is covered in these karst regions. Wisconsin is no stranger to this either, but also notice how glaciers impacted our state’s formations (we call that the driftless area but that’s for other posts to explain).
I did spot some additional trails above where the main paved trail ends but I’m not sure it connects directly here. I didn’t go further as the rocky surface gets incredibly slippery from the rain and moisture to the point it would be dangerous from here. (Edit from the future: Turns out I missed that on the map, it’s the Chubb Hollow Trail and you reach it from a different path a little closer to the Current River downstream of the spring.)
Looking straight up above the cliffs rise vertically for quite a distance. Per the sign much of the composition is dolomite but I’m seeing other spots with sandstone and calcium so it can be kind of a conglomerate at times. I’m not very skilled with geology but I think that calcium is what dissolves and creates the blue hues in the water. Thank you, rocks!
The caves above the spring are narrow and shallow and not suitable for exploration so don’t go inside (but they are neat to find).
Looking back down to the water where the spring flows to the surface, water is pumping upwards from the ground rapidly resembling something more like a hot tub jets. There’s a sign near the trail head that states “on an average day 288 million gallons of water flow from the spring, enough to fill Busch Stadium in St. Louis in only 33 hours.”
According to the National Park Service website, this is one of three natural springs that could be the largest one in the United States on any single day depending on local rainfall (the others being Idaho’s Snake River Spring Complex and Florida’s Silver Spring). Certainly watching as the water flows down the spring branch into the river it’s hard to imagine one that could be larger. So glad that I found this place – and by pure dumb luck!
Hiking Data
Just a short walk to the spring with no “hiking” necessary if you park at the nearest lot. Had I known trails from the campground existed I would have chose that route but either way is just fine.
Less than one third of a mile round trip, blink and it’s over with. Very easy and accessible for all ages and skills. It’s an interesting drive through the hills to get here and fairly remote but if you’re in the neighborhood don’t miss it.
