Onondaga Cave State Park

Onondaga Cave State Park protects one of the most spectacular show caves in Missouri — a state famously riddled with thousands of caves, earning it the nickname ‘The Cave State.’ Designated a National Natural Landmark, Onondaga Cave is a breathtaking underground wonderland of towering stalactites and stalagmites, massive flowstones, delicate formations and an underground river, all set beneath the forested hills along the Meramec River in the east-central Ozarks.

Discovered and developed as a show cave, Onondaga dazzles visitors on guided tours with its grand chambers and richly decorated formations, among the finest cave displays in the Midwest. The surrounding state park preserves the forested bluffs and the Meramec River, with a second cave (Cathedral Cave) offering lantern tours, along with hiking trails, river access and camping. With its magnificent cave formations, its underground river, its National Natural Landmark status and its scenic Meramec River setting, Onondaga Cave State Park is a treasured natural wonder of the Missouri Ozarks and a showcase of the Cave State’s subterranean splendor.

Onondaga Cave State Park centers on guided tours of the spectacular Onondaga Cave, with its towering formations and underground river, and lantern-lit tours of the more primitive Cathedral Cave. Above ground, the park offers hiking trails through the forested bluffs, access to the scenic Meramec River for floating and fishing, swimming, camping, and a visitor center interpreting the caves and karst. Cave touring, hiking, river recreation and nature study are the draws. The combination of the magnificent show cave, the second cave, and the Meramec River setting makes the park a premier and beloved destination in the Missouri Ozarks.

The cave stays a constant cool temperature year-round, so tours run in every season — summer is the busy peak (and the cool cave a refuge from the heat), while spring and fall offer milder surface weather, wildflowers or color, and the Meramec River at its best for floating. Winter is quiet, with the cave a constant retreat. The cave tours are rewarding any time; spring and fall are ideal for combining cave tours with river floating and the surface trails. Check tour schedules, which may be seasonal or reduced in winter.

Onondaga Cave, in Missouri’s famously cave-rich Ozarks, was discovered and developed as a show cave, drawing visitors to its magnificent formations; it was even featured at a World’s Fair era and the subject of ownership disputes over its underground beauty. Recognized as a National Natural Landmark for its outstanding formations, the cave and surrounding land became Onondaga Cave State Park, protecting the cave and the Meramec River bluffs for the public. The park preserves this subterranean wonder, a showcase of Missouri’s identity as ‘The Cave State,’ with thousands of caves across the Ozarks.

Onondaga Cave formed in the soluble Ozark dolomite and limestone, dissolved by groundwater over immense time to create the cave’s grand chambers, passages and an underground river. As mineral-rich water dripped and flowed, it deposited the cave’s spectacular formations — towering stalactites and stalagmites, massive flowstones, columns, draperies and delicate features — built up drop by drop over thousands of years. The dissolving of the carbonate rock and the slow deposition of the dripstone formations created this magnificent show cave, a classic and outstanding example of Ozark karst and cave geology.

Onondaga Cave shelters cave-adapted wildlife, including bats (some rare or endangered) and unique cave creatures in its dark passages and underground river, while the surrounding forested park and the Meramec River host white-tailed deer, foxes, wild turkey, a rich community of birds, and the fish and aquatic life of the river. The biodiverse Ozark karst landscape supports diverse wildlife, including cave specialists found in few other places. The park is a fine place for wildlife watching and birding above ground, while the cave protects its own distinctive subterranean life.

Onondaga Cave State Park protects a biodiverse Ozark karst ecosystem, where the cave and its underground river shelter cave-adapted creatures and bats (including rare and endangered species), and the surrounding forested bluffs and the Meramec River support diverse plant and animal life. The cave’s constant, fragile environment and the clean river are ecologically significant. Protecting the cave (and its bats, including from white-nose syndrome), the underground river, the river’s water quality and the forests sustains both the distinctive subterranean and surface ecology of this treasured National Natural Landmark in the Cave State.

Onondaga Cave, a National Natural Landmark and one of the most magnificent show caves in Missouri, holds a treasured place among the natural wonders of the Ozarks and showcases the state’s identity as ‘The Cave State.’ The spectacular formations, the underground river, and the cave’s storied history of discovery and disputes have drawn generations of visitors to marvel at its subterranean beauty. Set along the scenic Meramec River, Onondaga Cave State Park embodies both the underground splendor and the river-and-forest beauty of the Missouri Ozarks, a cherished and unforgettable destination.

Onondaga Cave State Park is in east-central Missouri near Leasburg, off State Route H from Interstate 44, about 75 miles southwest of St. Louis. The park is free to enter, but the cave tours charge a fee and run on a schedule (which may be seasonal). It offers guided tours of Onondaga Cave and lantern tours of Cathedral Cave, a visitor center, hiking trails, Meramec River access, camping and picnic areas. The cave tours involve walking, stairs and uneven, sometimes wet footing. Check Missouri State Parks for tour schedules, fees and conditions before visiting.

Missouri State Parks protects Onondaga Cave, its formations, its underground river and its bats, along with the surrounding forests and the Meramec River. Visitors help by taking only guided tours, never touching the fragile cave formations (oils from hands stop their growth), following bat-protection rules (including decontamination against white-nose syndrome), staying on trails, protecting the river’s water quality, packing out everything, and respecting wildlife. Protecting the cave, its formations and bats, the underground river and the river’s water quality sustains both the subterranean and surface ecology of this treasured National Natural Landmark.

Cave tours involve walking on paved but sometimes wet, uneven paths with stairs in the cool, dim cave — wear sturdy shoes with grip, bring a light layer (the cave is cool year-round), watch your footing, and follow the guide; never enter the cave without a guided tour. Cathedral Cave’s lantern tour is more primitive and rugged. Above ground, take care on the bluff trails and near the Meramec River (wear a life jacket when floating). Supervise children in the cave and near the river, and respect the cave’s hazards and the river’s currents.

The park is free to enter, but cave tours require tickets and run on a schedule. The cave may be entered only on guided tours; never touch the formations. Follow bat-protection and decontamination rules. Stay on trails above ground. Camp only in designated areas. Follow Meramec River fishing and floating regulations and licensing. Pets are not allowed in the caves and must be leashed elsewhere. Drones require authorization. Collecting is prohibited. Pack out all trash. Check Missouri State Parks for tour schedules and current rules before visiting.

The town of Leasburg, the Meramec River (a popular float stream), nearby Meramec State Park (with its own caves), the Mark Twain National Forest, and the east-central Ozarks lie near the park, with the city of St. Louis about 75 miles northeast. The Ozark karst country, rich with caves and rivers, defines the region. Onondaga Cave State Park anchors a scenic region of show caves, the Meramec River and forested bluffs in east-central Missouri, a centerpiece of a Cave State and river-touring adventure in the Ozarks.

Take a guided tour of the spectacular Onondaga Cave to marvel at its towering formations and underground river — book ahead and check the tour schedule (which may be seasonal) — and consider the more rugged lantern tour of Cathedral Cave for adventure. Wear sturdy shoes and a light layer for the cool cave, never touch the fragile formations, and follow bat-protection rules. Above ground, float or fish the scenic Meramec River, hike the bluff trails, camp in the park, and explore Missouri’s identity as the Cave State.