Longest tunnel in the world is in the US and runs 85 miles long
Published on Nov 10, 2025 at 2:17 AM (UTC-5)
by Molly Davidson
Last updated on Nov 10, 2025 at 2:42 AM (UTC-5)
Edited by
Kate Bain
Beneath New York lives the world’s longest tunnel.
You won’t see it, you won’t drive through it, but it’s there – running 85 miles underground.
It’s not a subway, not a road, and definitely not a tourist attraction.
It’s a lifeline, built nearly a century ago and still fueling one of the world’s biggest cities.
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The longest tunnel in the world has an important job
Running 85 miles under the state of New York, the Delaware Aqueduct is officially the world’s longest continuous tunnel.
It carries fresh water from the Rondout, Cannonsville, Neversink, and Pepacton reservoirs straight to Yonkers, where it feeds into the Hillview Reservoir – the final stop before New Yorkers turn on their taps.
Built between the late 1930s and 1940s, it’s a feat of old-school engineering that still outpaces modern projects.
31 shafts were drilled to access different sections at once, letting workers carve through solid bedrock with drills and dynamite before lining it all with concrete.
Even during WWII, they reinforced it to be bombproof.
Every day, this buried artery delivers up to 80 percent of the city’s drinking water.
That’s enough for more than 8.5 million people.
The only problem?
It’s been leaking for decades, losing as much as 35 million gallons a day.
A $1 billion repair plan launched in 2010, including a bypass tunnel under the Hudson River, but delays mean work won’t wrap until after 2027.
For now, the system still pumps out famously clean tap water straight from the Catskills.
Related
The world’s longest bridge is testing limits
The Delaware Aqueduct isn’t the only record-breaker hiding in plain sight.
Humanity keeps stretching limits just because we can.
Take the world’s longest bridge – China’s Danyang–Kunshan Grand Bridge – which runs 102 miles and was built to survive earthquakes and typhoons.
Or the world’s longest limo, the 100-foot American Dream that comes with a helipad, jacuzzi, and enough wheels to fill a parking lot.
With roles at TEXT Journal, Bowen Street Press, Onya Magazine, and Swine Magazine on her CV, Molly joined Supercar Blondie in June 2025 as a Junior Content Writer. Having experience across copyediting, proofreading, reference checking, and production, she brings accuracy, clarity, and audience focus to her stories spanning automotive, tech, and lifestyle news.
