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Mosier Twin Tunnels

From Oregon Hikers Field Guide

Milepost 72 is inside the East Mosier Tunnel (Steve Hart)
The east portal of the east tunnel (Steve Hart)
Tunnel portals (Steve Hart)



When the original Columbia River Highway was built through this area in 1921, it was necessary to build two tunnels to get through a high rock point. The west tunnel is 81 feet long and the east tunnel measures 288 feet. Rockfalls were always a problem and a timber lining was installed inside the tunnel to make them safer. Rockfalls continued outside and between the tunnels. In 1938, the tunnels were enlarged, but the continuing growth in the size and number of trucks rendered the tunnels obsolete. In 1954, a new road was opened near water level and the tunnels were abandoned. They were soon filled with rock rubble and forgotten. A trip to the west portal in the early 90s found the road near the tunnels completely buried in fallen rock with trees growing in the roadway. Only a quarter of a damaged tunnel portal was visible.

In 1995, work was begun to reopen the tunnels for tourist use. This involved the removal of the rubble, and rebuilding and resurfacing the road. The area opened to tourist use in 2000. The tunnels have many interesting features, including timber cribbing, two windows letting in light and providing views, stone arched portals and carved graffiti dating from the 1920s.

Safety has always been a concern in the area. Rockfalls were originally the primary concern and to protect visitors, the catchment structure was constructed as well as a roof over the 124 feet between the two tunnels. Unfortunately, after a tragic death, the state responded by constructing a fence barricade, keeping people inside the catchment structure. The recently restored walkway outside the tunnel was gated and bars now appear on the tunnel windows, detracting from the viewpoints.

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Guidebooks that cover this destination

  • 60 Hikes within 60 Miles of Portland by Paul Gerald - 2nd Edition

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Oregon Hikers Field Guide is built as a collaborative effort by its user community. While we make every effort to fact-check, information found here should be considered anecdotal. You should cross-check against other references before planning a hike. Trail routing and conditions are subject to change. Please contact us if you notice errors on this page.

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