Route 66 is known for neon lights, vintage diners, and kitschy roadside stops—but some of its wildest wonders are buried underground. From outlaw hideouts to prehistoric fossils and surreal rock formations, the Mother Road hides a whole world beneath its surface. Whether you’re chasing echoing legends or just want to escape the desert heat, these caves and caverns offer an unforgettable detour into the depths.
Missouri’s Limestone Legends
Meramec Caverns – The Jesse James Hideout
Distance from Route 66: Directly accessible from the Mother Road in Stanton, MO.
Meramec Caverns stands as perhaps the best stop along Route 66’s trek across Missouri, and one of the most enjoyable roadside attractions along the entire Mother Road. This limestone cave system has been advertising itself on barns and buildings throughout the Midwest since the 1930s, making it impossible to miss if you’re paying attention to the scenery.
The caves were first developed during the Civil War when natural saltpeter was mined for gunpowder manufacturing. Later, local farmers used the largest chamber for community dance, a tradition that continues today with Easter services and chamber of commerce meetings still held underground.
Jesse James, the famous outlaw, actually used these caverns as a hideout and once took advantage of the underground river to escape through a secret “back door.” You can still see evidence of his visits during the guided tours.
What makes Meramec special isn’t just its size, though the natural formations are among the most sculptural and delicate you’ll find, but also its wonderfully kitschy artificial additions. The hand-operated sound-and-light show ends with Kate Smith singing “God Bless America” while red, white, and blue lights project Old Glory onto a limestone curtain. It’s pure Americana that perfectly captures the Route 66 spirit.
Beyond the cave tours, you can also enjoy riverboat rides on the Meramec River, adding another layer to your underground adventure.
Practical Info: Open daily, $29.50 for adults. Guided tours, light shows, and riverboat rides are available.
Fantastic Caverns – America’s Only Ride-Through Cave
Distance from Route 66: Just off the route in Springfield, MO.
Fantastic Caverns in Springfield holds the unique distinction of being the only cave in North America offering a complete ride-through experience. Visitors enjoy a comfortable 55-minute guided tour aboard Jeep-drawn trams, making it accessible for families, elderly visitors, small children, or anyone with mobility concerns who might find traditional cave tours challenging.
The cave was first discovered in 1862 by John Knox and his hunting dog. Knox kept the cave’s existence secret during the Civil War to prevent exploitation for saltpeter mining. In 1867, when he finally advertised for explorers, twelve women from Springfield’s Women’s Athletic Club responded. Equipped with torches, lanterns, ropes, and ladders, they became the cave’s first official explorers, and their names remain visible, carved into the cave walls today.
The tour follows an ancient underground riverbed surrounded by impressive geological formations. Throughout the year, the cave maintains a consistent and pleasant temperature of around 60°F, providing visitors a comfortable experience regardless of the season.
Practical Info: Open daily from 8 a.m. until dusk, with the last tour typically departing between 5 and 6 p.m., depending on the season. General admission adult tickets are $34. Tickets are available on-site only, first-come, first-served.
Arizona’s Desert Depths
Grand Canyon Caverns – Sleep 220 Feet Underground
Distance from Route 66: Right along the route in Peach Springs, AZ.
Grand Canyon Caverns invites you to spend the night 210 feet below ground in what’s billed as the world’s deepest and quietest hotel suite. This unique subterranean suite, priced around $1,000 per night, comes fully equipped with modern amenities, including a private bathroom, TV, DVDs, and vinyl records.
Formed about 65 million years ago, these caverns are among the largest dry caverns in the U.S., known for their lack of humidity and perfect preservation conditions. During the Cold War, they were stocked as a government fallout shelter, and visitors can still see original supplies like crackers and candy.
Tour highlights include a perfectly preserved 150-year-old mummified bobcat and a life-size replica of a giant ground sloth named “Gertie,” which marks real claw prints left over 11,000 years ago. For an extra-special experience, visitors can dine at the underground Cavern Grotto or join thrilling ghost tours after dark.
Practical Info: Tours are temporarily closed for maintenance and expected to reopen by early June 2025. When open, tours run every half-hour from the gift shop and cost between $20 and $25 for adults, depending on the experience.
New Mexico’s Archaeological Treasures
Sandia Cave – Ancient History Above Albuquerque
Distance from Route 66: Approximately 15 miles north of Albuquerque.
Located near Placitas, New Mexico, Sandia Cave – also known as Sandia Man Cave – is a National Historic Landmark situated high on the steep walls of Las Huertas Canyon in the Sandia Mountains. The cave is accessible via a 0.47-mile hike from a marked trailhead off NM-165. The trail includes a concrete staircase leading to a limestone ledge, followed by a metal spiral staircase that ascends to the cave entrance.
University of New Mexico archaeologists spent four years digging through layers of history at this site, from 1937 to 1941. They found things like stone tools for hunting, scraps of woven baskets, pieces of yucca fiber moccasins, and bones from Ice Age giants like mastodons.
The discovery initially made headlines with claims of being the oldest human site in North America. Those early estimates have since been walked back – the evidence now points to occupation around 10,000 to 12,000 years ago rather than the original 25,000-year claim. Still, that’s plenty old enough to matter. The cave remains important for piecing together how people lived in the Southwest when the climate was completely different and massive animals still roamed the landscape.
Visitors can enjoy panoramic views of the Cibola National Forest and the Sandia Crest from the cave’s entrance. The site is undeveloped and requires self-guided exploration; flashlights are recommended. The area has also experienced vandalism and graffiti, so visitors are encouraged to be respectful.
Practical Info: Free to visit, but requires a moderate hike. Follow NM-165 through Placitas to the marked trailhead.
Note: Not a commercial tour cave, more rustic.
Oklahoma’s Gypsum Wonders
Alabaster Caverns – World’s Largest Gypsum Cave
Distance from Route 66: About 2 hours north of Oklahoma City.
About two hours north of Oklahoma City, Alabaster Caverns State Park protects the largest natural gypsum cave open to the public worldwide. The cave formed in a 200-million-year-old gypsum bed, creating pure white and pink formations that look completely different from typical limestone caves.
The three-quarter-mile guided walking tour takes about 45 minutes through vast gypsum formations and stays at a constant 60°F year-round. Unlike harder limestone caves, gypsum is soft enough that you can actually scratch it with your fingernail.
The park also offers hiking trails, camping, and picnic areas above ground. It’s especially beautiful in spring when wildflowers bloom across the prairie above the cave.
Practical Info: Open year-round with seasonal hour variations. Guided walking tours are available daily from 9 a.m. to 4 p.m., on the hour.
Admission: $10 for adults, $8 for seniors and military, $7 for kids 6–12.
Note: Wild caving is not available from October 1 to April 30 due to bat hibernation.
California’s Desert Finale
Mitchell Caverns – Limestone in the Mojave
Distance from Route 66: Located within the Providence Mountains State Recreation Area, approximately 20 miles north of Essex, California.
Mitchell Caverns offers a unique limestone cave experience in the heart of the Mojave Desert. Formed within Permian-age marine limestone of the Bird Spring Formation, the caverns were sculpted by groundwater rich in carbonic acid, creating impressive speleothems, including stalactites, stalagmites, helictites, and flowstone.
The caverns are part of the Providence Mountains State Recreation Area and are surrounded by the Mojave National Preserve. They were developed as a tourist attraction in the 1930s by Jack and Ida Mitchell, who built stone structures that still stand today.
Tour Information:
- Access: Tours are by reservation only and must be booked through ReserveCalifornia.com.
- Schedule: Tours are offered Friday through Sunday and on holiday Mondays. From October to May, tours are at 11 a.m. and 2 p.m.; in June and September, tours are at 10 a.m. The park is closed in July and August.
- Duration: Each tour includes a 0.5-mile round-trip hike and a two-hour guided exploration of the caverns.
- Note: The access road is paved but rough, and the trail to the cave entrance is moderately steep, requiring about a 15-minute uphill walk.
