26 Hidden Tunnels and Secret Hideouts Used During the Civil War

Military History
By Jasmine Hughes

The Civil War wasn’t just fought on battlefields—it was waged underground, behind walls, and in the shadows. From smuggler tunnels beneath Southern mansions to Union hideaways carved into rock, these secret locations played a pivotal role in espionage, escape, and survival. Here are 26 of the most fascinating hidden tunnels and covert hideouts used during America’s bloodiest conflict.

1. The Burnside Tunnel

© Civil War Academy

This clandestine tunnel helped General Ambrose Burnside hold Knoxville by enabling discreet movement of troops beneath enemy lines.

2. Oak Alley Plantation

© Travel Buddies

Rumored to contain a network of tunnels beneath its stately grounds, Oak Alley was allegedly used to shelter wounded soldiers and escaped prisoners.

3. Fort Morgan Escape Tunnel

© Tripadvisor

This coastal fort concealed a tunnel used by Confederate soldiers to evade Union capture during the siege of Mobile Bay.

4. Andersonville Escape Tunnel

© New Georgia Encyclopedia

Prisoners at this infamous Confederate POW camp dug numerous escape tunnels, though few led to successful freedom.

5. Mammoth Cave Hideout

© Wikipedia, the free encyclopedia

The vast cave system was used to store munitions—and possibly as a rendezvous point for Confederate scouts.

6. The Underground Railroad Routes

© USA Today

Though predating the war, many of these tunnels were reactivated to assist runaway slaves and Union scouts in enemy territory.

7. Monticello Slave Tunnels

© Time Travel Turtle

Thomas Jefferson’s estate included hidden corridors used in the antebellum period, which were allegedly repurposed during the war.

8. White House of the Confederacy

© American Civil War Museum

Rumored to have secret passageways beneath it for Davis’s quick escape, though these have never been conclusively proven.

9. Honey Hill Fortifications

© AllTrails

Underground bunkers and trenches formed a hidden network that allowed for stealth troop movement during the 1864 battle.

10. Rose O’Neal Greenhow’s Washington Safe House

© Britannica

This Confederate spy operated from a townhouse with hidden rooms and trapdoors, storing documents and hosting covert meetings.

11. Vicksburg Siege Tunnels

© The Vicksburg Post

Civilians and soldiers alike carved out “bombproofs” and escape routes during the Union siege that lasted over 40 days.

12. Pine Bluff Hideouts

© Wikipedia, the free encyclopedia

Union soldiers and loyalists reportedly used secret forest shelters to evade Confederate patrols in this contested town.

13. Tunnel Hill

© www.civilwarrailroadtunnel.com

Part of the Western & Atlantic Railroad, this tunnel was crucial for transporting Confederate troops and was a target for Union raids.

14. Libby Prison Escape Tunnel

© Encyclopedia Virginia

Union officers famously tunneled out of this Confederate prison in 1864. Over 100 men escaped through the underground route—making it one of the most daring escapes of the war.

15. Fort Donelson Earthworks

© Cumberland River Basin

Earthen forts here included hidden passageways and tunnels to move supplies and reinforcements unseen by Union artillery.

16. Cahaba Prison Drain Tunnel

© HubPages

Prisoners used this small drain tunnel in a daring escape attempt, though most were quickly recaptured.

17. Blenheim House Cellar

© Fairfax County

This Union-occupied farmhouse featured graffiti-covered walls and secret compartments in the cellar for stashing documents and weapons.

18. Sabine Pass Entrenchments

© Warfare History Network

Engineered with hidden firing positions and crawlspaces, the fort’s defenders used them to repel Union naval attacks.

19. Fortress Monroe Escape Routes

© American Battlefield Trust

Union forces stationed at this vital coastal stronghold created tunnels to shield against Confederate bombardments.

20. Hatcher’s Run Trenches

© Stone Sentinels

This battle site included labyrinthine trench systems that connected to underground bunkers and command posts.

21. Mosby’s Confederacy Hideouts

© Past Lane Travels

Colonel John Mosby and his rangers used barns, caves, and abandoned cabins to launch lightning raids and vanish into thin air.

22. Tunnel Beneath the Tennessee State Capitol

© Flickr

Built pre-war, this tunnel was used to store munitions and allow safe movement when Nashville fell under Union control.

23. Fort Pillow Earthworks

© Burnsland Archives – Burnsland Hub

Extensive trench systems with hidden magazines were built into the bluff, making them difficult to detect from the river.

24. Tunnel System Under Charleston

© Post and Courier

Used for moving arms and evacuating key figures as Union troops closed in. Some reportedly connected to harbor escape routes.

25. Kentucky’s Crystal Onyx Cave

© National Park Service

Used as a temporary hideout for Confederate bushwhackers avoiding capture after raids on Union outposts.

26. Union Bunker at Cold Harbor

© American Battlefield Trust

Some of the most brutal trench warfare occurred here, with reinforced tunnels protecting men from relentless shelling.