Zion-Mount Carmel Highway, Tunnel, Two miles east of Zion Canyon Scenic Drive, Springdale, Washington County, UT

Significance: The 5,613-foot long, rock-faced Zion-Mount Carmel Tunnel with concrete spines was completed in 1930 and retains structural integrity. It is one of the most spectacular manmade sites at Zion National Park and is the only one of its kind in the Rocky Mountain Region.
The tunnel is the longest constructed vehicular tunnel in the National Park system (5,613'), and in the western United States at the time of its completion. Aspects of its construction are unique, such as initial boring through side galleries rather than entrance portals. The tunnel is also significant for its association with the Zion-Mount Carmel Highway, the most expensive and one of the most difficult highways constructed by the National Park Service at its completion in 1930.
Unprocessed Field note material exists for this structure: N200
Survey number: HAER UT-39-A
Building/structure dates: 1930 Initial Construction
Building/structure dates: 1951 Subsequent Work
Building/structure dates: 1958 Subsequent Work