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The Eerie Tweed Tunnels

Explore an old World War I shooting range in Blauvelt State Park with an expansive network of underground tunnels – enter the darkness if you dare.

tweed tunnels, clausland mountain, blauvelt state park, hiking, nyack new york

The History

In 1910 Clausland Mountain, in current day Blauvelt State Park of Nyack, New York was cleared of its trees to construct a revolutionizing rifle range. The range was a money blunder and a nightmare for local residents who complained about bullets falling from the sky. By 1913 the range was closed, later to be used as Christian camp for women and then a homeless shelter before being vacated and reclaimed by the forest.

The rifle range compound used above and below ground tunnels for soldiers to travel around and avoid the range activity. These tunnels and walls are what remain today to be explored.

tweed tunnels, clausland mountain, blauvelt state park, hiking, nyack new york

About The Hike

Blauvelt State Park is home to several miles of trails which have light elevation gain. The trails range from not very well-marked to not-marked at all. The trails also range from well maintained to never seen a pair of clippers come through, ever.

Regardless of this neglected trail system in an otherwise obscurely random park, this is an awesome hike and if you’re here to explore the tunnels, for the better part of the hike you won’t even be on these trails.

tweed tunnels, clausland mountain, blauvelt state park, hiking, nyack new york

It would be awfully painful for anyone to try and give exact directions to the tunnels based on the poor markings I mentioned and thus I’ll give some general ones that are guaranteed to land you in the right spot.

This AllTrails link will get you to the tunnels, you can also park in several other locations to access this Blauvelt and search the Tweed Tunnels on Google Maps. This will give you the general direction to walk in which I found to be accurate enough. All of the tunnels and walls connect to each other so once you come across one graffiti-stricken wall, you should be able to explore and seek out everything you’re looking for.

tweed tunnels, clausland mountain, blauvelt state park, hiking, nyack new york

It is said the tunnels have miles to be explored so if you are a creature of the dark, this is a place for you. I am not – I did have a grand time exploring from the outside and taking in the ‘urban art meets mother nature’ vibe.

Some people go to Cambodia to see ancient temples overgrown by trees and their roots but you don’t even need to leave New York to get this! What an insane entrance to one of the Tweed Tunnels!

tweed tunnels, clausland mountain, blauvelt state park, hiking, nyack new york

Getting There and Important Information

This park is one of those random state parks that doesn’t get much attention. I doubt you’ll ever see what most consider to be a crowd, and don’t think parking in one of the many lots will be an issue.

I parked at the lot on Greenbush Rd which I took to be the closest to the tunnels, the AllTrails link to Clausland Mountain Rd is also similar distance. Parking on N Greenbush Rd is the most substantial of the parking lots but will require a further hike.

Bring a flashlight or headlamp if you’re planning to explore the tunnels – they become pitch black. Also, there are many reports of spiders and crickets in the thousands so maybe bring bug spray too?


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Photography exclusively by Dan Oliver unless otherwise stated and cited. Embedded maps are provided by Embed Google Map ( and map images shown are provided as stated and cited.


This website is provided for entertainment purposes only, and is not meant to serve as an instructional guide, or present itself as an authority for any of the locations written about. The locations mentioned, written, and photographed herein are nothing more than my personal adventure archive. If you are interested in visiting any locations you should not depend on the information in this website to plan any excursions. You should research a wide variety of informational sources, websites, hiking guide books and maps found elsewhere. Many locations are dangerous and potentially illegal to access which can lead to fines, injury or death even when prepared. I do not encourage anyone to trespass or put themselves or others in way of harm. This website, and therefore its’ owner/author, cannot assume any responsibility for anything you may incur while hiking or exploring any of these locations or anywhere on planet earth. Thank you for viewing!


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