Missouri's underground hiking scene is all about the limestone


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When I moved to Kansas City from Oregon nearly 15 years ago, I thought my hiking days were over. Compared to the Pacific Northwest, most of Missouri has the topographical charm of a pane of glass. Trails in the western part of the state were scarce, and what few I had discovered during my first months weren’t worth braving the humidity or the hordes of ticks.


I soon discovered I was dead-wrong. The Show-Me State boasts a variety of hiking options that include waterfalls and streams, national forests and wilderness areas, grasslands, and even mountains. (That’s right, mountains. At 1700 feet, the St. Francois range in southeast Missouri isn’t the highest in the nation, but I feel they deserve a pass, given they formed nearly a billion and a half years ago. The Rockies, in comparison, date back only 150 million years.)


I got a good taste of the state’s spread of outdoor offerings during my stay, but what really got me hooked on Missouri hiking was the limestone. Not the sedimentary rock itself, but rather the karst topography that forms when the carbonate bedrock erodes.

“Karst” is geology-speak for cavey, and you can find it everywhere in Missouri (whose other nickname is The Cave State.) Over 6,000 caves perforate the massive, sometimes-mile-thick layers of limestone deposited across Missouri by marine animals between 500 million and 65 million years ago, when it consisted of shallow seas and coastline.


For millions of years after the seas receded, naturally acidic rainwater went to work like vinegar through baking soda, carving out a subterranean network of karst features: caves, sinking streams (water that trickles through the ground, into a cave,) underground channels (streams that run through a cave,) springs (streams that seep back out of the ground from, you guessed it, caves)—you get the picture. As the limestone further dissolved, the caves collapsed and eroded to form other karst features like sinkholes (a cave whose roof fell in), karst valleys (an even older collapsed cave), and natural bridges (a standalone arch-like remnant of a collapsed cave.)


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The end result of all this cave formation and destruction is a geological wonderland with hikes that fuel the imagination as they weave over, under, and through some fairly exotic and exciting micro-terrain.


The Katy Trail


My first taste of Missouri limestone was on the Katy Trail near Rocheport. Named for the K and the T in the Missouri-Kansas-Texas Railroad, the path follows the right-of-way of a defunct railway that paralleled the Missouri River eastward, before veering southwards through Kansas and Oklahoma, and into Texas. There’s not much in the way of karst topography along The Katy, but it does offer an unrivaled profile of the massive slabs of intact limestone bedrock needed to begin karst formations.


Taken in segments, the Katy Trail is hardly a challenge; it’s almost completely flat, and it’s paved with crushed limestone. But the 240-mile trek as a whole stretches across most of Missouri, from east to west, with more than two dozen trailheads along the way that link into the trail. Daytrips along the Katy showcase 300-foot tall limestone bluffs carved out by the mighty Missouri River, with spur trails that overlook valleys, wetlands, farm fields, and deciduous forests across the state.


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Like much of Missouri’s hiking, the Katy Trail offers a smorgasbord of history along the way. Much of it is railroad-centric: restored depots and stations, out-of-use rail bridges, train cars and signals, and even an explosives bunker and train tunnel. Scores of interpretive signs also point out historic sites, such as Lewis and Clark’s journey up the Missouri, sunken steamboats, and Civil War battlefields.


If you’re looking to hike (or bike) the longer haul, you can tackle the entire Katy a day at a time, jumping off at any of the trailheads to check into one of the many bed and breakfasts found in the towns along the way. Many of these small communities showcase their steamboat and railroad histories by way of museums, art galleries, and interpretive sites.


Ha Ha Tonka State Park


To literally delve a bit deeper into the limestone, head south, past the Lake of the Ozarks, to Ha Ha Tonka State Park. It has around 15 miles of trails that offer a sampling of cave formations, so you’ll get a taste of everything karst has to offer.


The Colosseum Trail, in particular, meanders through a 500-foot-long sinkhole formed after a length of cave collapsed. The 150-foot-deep depression resembles a tree-lined stadium in the landscape. At the far end of the hike is a remnant of the original cave, a 70-foot wide natural bridge. The trail loops a figure-eight under, around, and then over the rock overpass.


If you’re up for a bit more cardio, the Spring Trail follows the shoreline of the Lake of the Ozarks, past Ha Ha Tonka Spring, then through some large boulders that were once part of the ceiling of another section of collapsed cave. When the trail reaches the base of a limestone bluff, you can look forward to a 200-foot, 316-stair scramble straight up the side. At the top are sweeping views of the karst valley, as well as distant glimpses of the historic centerpiece of the park, the burned-down sandstone remnants of a 1902-built, European-style castle built by a wealthy Kansas City businessman who owned the land decades before it became a state park. (There’s a short, separate trail to view the castle up close, as well.)


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Other features that grace Ha Ha Tonka’s network of trails include the Devil’s Kitchen, a small cave decked out with a “chimney” (a tiny skylight-sinkhole in the rear of the cave;) a concave limestone bluff called the Devil’s Promenade; and Balancing Rock, an oblong boulder precariously perched upright near the Ha Ha Tonka Spring runoff.


Rock Bridge Memorial State Park


Five miles south of Columbia, in central Missouri, is a unique opportunity to see old karst and new karst side by side. Rock Bridge Memorial State Park offers similar geological sights as Ha Ha Tonka, including its own namesake natural bridge, sinkholes, springs, and underground streams. The park also lets you explore a cave firsthand to get a glimpse an un-collapsed cave from the inside, complete with underground stream. (Most caves in Missouri’s state parks are gated off to protect hibernating bat populations.)


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The star hike of the park, Devil’s Icebox Trail winds its way alongside a stream through a long, ancient sinkhole, making its way under a 63-foot-high rock bridge. Towards the end of the trail, the cave system is still intact; the depression drops even deeper into the always-56-degree Devil’s Icebox, a double sinkhole that is actually a cave-in in progress. Further along, the stream re-emerges from its source, 166-foot long Connor’s Cave. Visitors are welcome to poke around in the river cave, provided they bring their own flashlights.

In the three short years I spent in Missouri, I came to appreciate its own natural order, including, believe it or not, the ubiquitous lone star ticks. I flat out fell in love with the Midwest’s hair-raising thunderstorms, the unrivaled spring catfish- and bass-fishing, the balmy weather that lasts until October, and the autumns that set the landscape aflame with color. But for me, karst geology was at the top of the heap. It’s the true natural gem of Missouri, and one that lies poetically—if not literally—below the state’s surface, just waiting to be discovered.

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