Overview

Hype:

The Morrison Knudsen Tunnels were part of a Cold War era program by the United States Department of Defense (DoD) and the United States Army. The tunnels are Located in the Buckhorn Wash area of the Rafael Swell in Utah. The contractor Morrison-Knudsen built horizontal tunnels in the Navajo Sandstone beginning around 1948, with the purpose of studying underground structures and how explosives detonated on the surface affected them. The tests reportedly included multiple blasts, ranging from hundreds of pounds of explosive to up to 320,000 lbs in the largest detonation. The goal was to evaluate the effects of disturbances on underground structures for military-engineering purposes. Today, the site is accessible to view along Buckhorn Draw Road. There is a pull-out with an informational panel and a short walk to one of the tunnel entrances. The tunnel is gated for safety.

Cave Type: Horizontal

Time:

Fees: None

Recommended Ages:

	0-3
	4-11
	12-19
	20-49
	50-69
	70+

Recommended Months to Visit:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Permits: Gated

Links: https://www.coldwartourist.com/mk-tunnels
https://www.roadtripryan.com/go/t/utah/san-rafael-swell/mk-tunnels

Maps

Closest City or Region: Castle Dale, Utah

Coordinates: 39.164053, -110.736070

Interactive Guide Map

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May 25, 2025 Trip Report

By Jeremy Dye

Trip Members

Jeremy Dye, Tara Dye,

Story

Tara and I hiked to the Morrison Knudsen tunnels and Ruin Arch. 

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