Underground Chicago: Exploring The Hidden Layers of the City

The term ‘Chicago architecture’ usually evokes images of soaring skyscrapers, but the architecture of underground Chicago is fascinating and essential in its own right. Virtually unknown layers of tunnels, passages, sewers, pipes, and other infrastructure crisscross below the city. 

We research stories from Chicago history, architecture and culture like this while developing our live virtual toursin-person private tours, and custom content for corporate events. You can join us to experience Chicago’s stories in-person or online. We can also create custom tours and original content about this Chicago topic and countless others.

The Pedway System

Chicago Pedway basement levels
This Pedway goes under Daley Center.

The most user-friendly layer of Chicago’s underground is the Pedway System. The term “Pedway” is a conjunction word formed from “pedestrian way.” A busy city like Chicago is always looking for ways to drop syllables for efficiency!

Functionally, the Pedway is a collection of hallways in basements which connect buildings, train stations, and underground parking structures in the Loop. Small parts of the Pedway consist of “skybridges” that link the upper floors of adjacent buildings and passages that stay on the street level by cutting through lobbies.

You can also use our handy Pedway map to explore this essential layer of underground Chicago. Our custom content creators can help create similar material for you, as well.

Underground Streets

underground Chicago lower Wacker Drive
Photo by Paul Sableman via flickr

The most-viewed portion of underground Chicago underground is probably its underground streets, such as Lower Wacker or Lower Michigan. Movies like The Dark Knight and The Blues Brothers have immortalized these dark concrete spaces. But even locals often do not know exactly why this part of underground Chicago exists.

Our multi-layered city has lower levels of streets in some parts of the Loop and River North because it allows easy access for freight transport and trash disposal. That, in turn, make the street-level less crowded. Some sections, like East Randolph near Maggie Daley Park, are even triple-decked.

A great thing about the multiple layers is that it keeps the trash away from where most people work, live, and commute. That means it keeps the rats away from pedestrian level as well.

Sewers of Underground Chicago

Underground the streets of Chicago, below the Pedway and below the underground streets, you will find the sewers. While no human should actually want to explore these, it is where our population of 2-3 million rats live.

It’s gross to imagine that many rodents, but it’s a reasonable number for a city of our size (you don’t want to know how many are in New York). Most cities have as many rats as human residents, if not more.

‘L’ Lines and Abandoned Freight Train Tunnels

underground Chicago freight tunnels
Abandoned freight tunnels pepper underground Chicago. Image via Wikimedia

Along with the Pedway and the Blue and Red ‘L’ lines sits a set of abandoned freight train tunnels. Constructed in the early 20th-century, these tunnels transported coal and provided underground space for telephone wires. Newer and cheaper infrastructure passed them by in the 1950s and people began to forget they were even there.

It took a true Chicago fiasco to remind everyone they were there. A construction crew accidentally broke a hole in one of the tunnels in the early 90’s. That hole happened to be below the Chicago River, near the famous Kinzie Street BridgeWater came pouring into the tunnel and caused massive flooding in basements throughout downtown. The deluge ultimately caused more than a billion dollars of damage! Afterwards, the city installed watertight bulkheads to seal off the underground freight and cable car tunnels tunnels.

underground chicago water tower water crib tunnel
The iconic Water Tower drew fresh water to the city via a hidden 10,000 foot tunnel. Image via Wikimedia

Water Tower Pumping Station

According to WBEZ, the Pumping Station at the Historic Water Tower drew water from Lake Michigan via a five-foot tall brick-lined tunnel that ran underground and out to a water intake crib. The tunnel is more than 10,000 feet long and is still in existence, but the city refuses to comment on its exact location or current usage. So mysterious!

To be perfectly honest, I was pretty stunned when I discovered that the Pumping Station is still in operation. I wandered in one day, felt blown away, and have loved taking private tour guests there ever since.

The Deep Tunnel System WAY Underground in Chicago

The least-known or understood feature of the Chicago underground would be the TARP system, better known as the Deep Tunnel. In the city that lives by the mantra of “make no little plans,” the city has undergone one of the largest and longest civil engineering projects in American history.

It has cost billions and taken decades to construct the Deep Tunnel. Now that it’s functioning, it’s supposed to keep storm water runoff from contaminating the lake and prevent catastrophic flood conditions. The tunnels are often underneath existing waterways, like the Chicago River. They work to funnel excess water to reservoirs and run-off canals on the city’s edges.

That said, Chicago does still see flooding when conditions are rainy enough, leading to criticisms. The arguments goes that the region may have been better served by creating a greener catchment basin, rather than just adding more to underground Chicago.

You never quite know what’s underneath your feet in Chicago. Or what’s above you, for that matter.

– Amanda Scotese and Alex Bean


Chicago Detours is a boutique tour company passionate about connecting people to places and each other through the power of storytelling. We bring curious people to explore, learn and interact with Chicago’s history, architecture and culture through in-person private group tourscontent production, and virtual tours.


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Private Tour Coordinator and Tour Guide

There is no shortage of things to discover in Chicago—I love being an urban explorer and uncovering its hidden places. I have an MA in Public History from Loyola University Chicago, and I have worked as a museum educator and kindergarten teacher. My desire to learn new things fuels my passion for educating others, which I get to experience every day as a Chicago tour guide. I live in the northern neighborhood of Rogers Park.

“Our guide Ellen was exceptional and gifted with a great personal touch.”


Tour Guide

Whether you are a first-time visitor or a lifelong resident, the vibrant history and modern majesty of Chicago never ceases to amaze. I’m a graduate of Columbia College with an M.A. in Interdisciplinary Art. I’ve worked for many years as an educator at City Colleges of Chicago. As tour guide at Chicago Detours, I integrate my enthusiasm for culture and architecture with my passion as an educator. West Town/Noble Square area is home for me.

“Jen was a perfect storyteller and kept us spellbound for hours.”


Tour Guide

With our Chicago neighborhoods, vibrant cultural institutions and nearly two centuries of larger-than-life stories, there’s never a dull moment here! I’m a fifth generation Chicagoan and a graduate of Washington University in St. Louis. In addition to guiding tours, I’m a creative writer and amateur genealogist. I also enjoy the city’s dynamic theater scene. You can also read overlooked stories from 19th-century newspapers on my “Second Glance History” blog. I live in River North.


Tour Guide

Chicago is unique as it always evolves into the future while holding on to the past. I’m fascinated by how people latch on to old architecture but happily pave over others. My background is in theater and performance and I’ve been a tour guide here for more than 10 years. Currently I’m finishing my Master’s in Public History at Loyola University because I love to teach the history of this scrappy city. I’m in the Edgewater neighborhood.


Operations Coordinator and Tour Guide

Chicago’s history is so fascinating, you could spend a lifetime uncovering its secrets…I’m willing to give it a try! I have an M.A. in US History from the University of Nevada-Las Vegas and then pursued doctoral studies in Urban History at the University of Illinois at Chicago. I love to learn new aspects of Chicago’s rich history and then share my knowledge as a tour guide with Chicago Detours. I live in Ravenswood.

“Marie was a bubbling fountain of information and contagious enthusiasm.”


Operations Coordinator and Tour Guide

As a fourth generation Chicagoan, I have been living and loving Chicago by bike, on foot, public transit or automobile. I am a graduate of UIC where through the College of Urban Planning and Public Affairs, began my eagerness to understand the nature, history and impacts of urban planning and development. It is incredibly rewarding to give back to this wonderful city by helping out in the office of Chicago Detours. I live in the incredibly diverse neighborhood of Albany Park.
“Sonny was extremely knowledgeable about all things Chi-town.”
Wade K


Content Manager and Tour Guide

Chicago has so many neighborhoods, buildings, and by-ways that it’s hard to go long without seeing something new, or something familiar from a new angle. I studied Cinema History for my M.A. from the University of Chicago. I’ve worked as a culture writer for various publications and as an educator of the humanities at the City Colleges of Chicago. I’m thrilled to share my love of this city’s busy past and unique architectural spaces with Chicago Detours. I live in the Chicago neighborhood of Lincoln Park.

“Alex was fascinating to listen to. He clearly knows his history and it shows.”
Katie K

Amanda Scotese

Executive Director and Tour Guide

I’m an interpreter of personal stories from the past and the city’s landscape. I love to imagine what originally happened inside old unmarked buildings, and what forces have shaped their design. I studied Chicago history, architectural history, and anything Chicago-related through my M.A. in the Humanities at the University of Chicago. My love for stories was enriched by my B.A. in Literature from the University of Michigan. I’ve written travel articles for publications like Rick Steves’ Italy best-selling travel guides, the San Francisco Bay Guardian, and The Chicago Food Encyclopedia. I live in the Chicago neighborhood of West Avondale.
“You can TELL Amanda is hyper-passionate about doing the research and getting the story that nobody’s heard before.”
Shelby F

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