11 U.S. Cities With Secret Underground Tunnels You Can Actually Visit

Most people exploring a city focus on what’s above ground. But in several cities across the U.S., there's an entirely different story beneath your feet. These tunnels, ranging from historic passageways to repurposed business routes, are open to the public. They may not be glamorous, but they carry real stories, strange functions, and strong local character.

If you’re curious enough to explore below street level, here are some U.S. cities where you can do exactly that.

Chicago, Illinois

There’s a network under downtown Chicago that connects more than 40 blocks through narrow corridors and stairwells. It’s called the Pedway, and during a weekday, it’s full of commuters darting between offices and train stations. The older freight tunnels, once used for coal deliveries, sit lower and remain closed. Those haven’t seen traffic in decades.

Seattle, Washington

The massive fire that tore through Seattle in 1889 didn’t just destroy the city—it set the stage for a whole new one to rise above it. Instead of demolishing the old streets, the city simply built on top. Now, visitors can walk the original sidewalks, complete with burnt wood beams and glass skylights overhead.

Indianapolis, Indiana

Beneath the Indianapolis City Market, a grid of brick-lined halls stretches underfoot. What’s left of Tomlinson Hall, which burned down in the 1950s, is now known as the Catacombs. No bones or coffins, but simply storage rooms built to keep food cool before refrigeration took over.

Portland, Oregon

Portland has its own version of subterranean folklore, and it starts under the old Chinatown district. These passageways were reportedly used in the late 1800s to abduct men for maritime labor. Today, tourists can walk the tight routes and hear the darker chapters. Dim lights, rusted bars, and unfinished walls make the past feel just close enough to touch.

New York City, New York

Indiana isn’t the only place with burial vaults worth exploring. In fact, Manhattan has a working crypt underneath St. Patrick’s Old Cathedral. These vaults aren’t theatrical or elaborate, but they’re still in use. The tight brick passages feel oddly removed from the city noise just overhead on Mulberry Street.

Boston, Massachusetts

Only a handful of people know Boston’s Old North Church for its place in Revolutionary history, but fewer realize that more than 1,000 people are buried right under there. The space feels quiet and cramped, which is a sharp contrast to the polished sanctuary above. Around the North End, forgotten tunnels from the Big Dig lie hidden and serve as reminders of how the city has rebuilt itself.

Los Angeles, California

During the 1920s, Los Angeles hid an aspect of its nightlife below the streets. Tunnels snaked between courthouses, jails, and city hall, often doubling as smuggling routes and speakeasy connections. Parts of that network are accessible on walking tours. You’ll find scratched-out maps, rusting rails, and faded signs pointing to rooms that haven’t seen daylight in years.

Washington, DC

At the Franciscan Monastery in Washington, DC, religious visionaries created catacombs that replicate ancient Christian burial sites. Today, they stand as a spiritual stand-in for the Holy Land. People often stroll past symbolic graves and relics, including the bones of a Roman child martyr.

Newark, New Jersey

Under St. Joseph’s Church in Newark, a crypt built in the 1930s houses wax replicas of saints instead of actual remains. Father Mateo Amoros, inspired by the catacombs seen in Montreal, created this display to sidestep burial laws. However, public access is limited and can be arranged by approaching the church.

Las Vegas, Nevada

Underneath the Strip in Las Vegas lies a network of flood channels that stretches for miles. These concrete corridors, built initially to manage storm runoff, now shelter a large underground population. Nonprofits take tourists through certain parts, offering context to a place few ever see.

Houston, Texas

What began as a simple connection between two buildings has grown into a seven-mile network beneath downtown Houston. The system now links dozens of skyscrapers and offers a cool, calm alternative to street-level chaos. Cafes, shops, and food courts also serve the city’s workforce during the day.

Dallas, Texas

In the 1970s, Dallas decided to take part in its downtown underground. The tunnel system connected banks, office towers, and retail spaces in a bid to combat the summer heat. You’ll still find a few shops and food counters if you enter through the right building. These walkways aren’t obvious, and there’s little signage.

Denver, Colorado

If you’re interested in how government buildings actually function, the network sitting below the Colorado State Capitol is worth a look. Built for heating and maintenance, they continue to house leftover marble, old tools, and even cat paw prints set in concrete. Some public tours include access, though not all, so it’s worth checking ahead.

Kansas City, Missouri

Who could’ve thought a thriving business hub would exist hundreds of feet beneath the city? SubTropolis, carved into ancient limestone below Kansas City, spans 55 million square feet and maintains a naturally cool climate year-round. While not open for casual visits, occasional tours and events provide access.

Cincinnati, Ohio

This space tells the story of how Cincinnati honored its ancestors while adapting to a growing city. The site can give you a view into 19th-century burial practices, where relocated graves were placed under St. Francis Seraph Church after the initial cathedral site was cleared.