The Tooth Rock Viaduct

Designer: L. W. Metzger
Engineer: Oregon Highway Department
Length: 1.5 miles
Year Built: 1915
Cost: $24,000

Tooth Rock Viaduct

Constructed in 1915, the tooth rock viaduct was a bridged roadway built into the rock hillside around the Tooth Rock Bluff. One and a half miles long, it is located between Eagle Creek and Tanner Creek. It offers magnificent views of the Columbia River and Bonneville Dam. It has been described as a hanging bridge on a rock face. This engineering feat was a compromise between a tunnel and a bridge. The cliff side was blasted to form a shelf where a viaduct could be constructed. Half of the roadway was laid on this ledge while the other half was built out on an overhanging viaduct. This unique section of roadway was part of the original CRH from 1916 thru 1937. The construction and opening of the Tooth Rock Tunnel in 1937 rerouted traffic underneath this portion of the highway. It was abandoned and sat dormant for many years. From the 1940's thru the 80's, it was neglected and began falling apart. In 1996, concerned citizens formed an organized group to oversee the restoration process of several sections of the CRH. This part of the old highway is the first phase in rebuilding the entire highway from Troutdale to The Dalles. The rebuild on this section was completed in 1996. It now serves as a bike and walking trial.

The photo below was taken from a postcard dated 1916

Below, construction crews pose with their horses after completion of the viaduct in 1915.

Work gangs of men construct the viaduct roadway with form boards, reinforced concrete and steel girders in 1915.

Mitchell Point Tunnel

Designer: John A. Elliot (University of Washington) State Highway Engineer: Henry L. Bowlby (West Point Graduate) Tunnel Length: 385 feet Cost to Build: $50,000 Year Tunnel was Built: 1915 Rock Type: Basalt The Tunnel of Many Vistas

The Mitchell Point Tunnel was bored thru a rocky cliff overhanging the Columbia River. It was 385 feet long with 5 arched windows with parapets and benches to sit on. The large projecting rock cliff was called "Little Storm Crest" by the Indians. The large mountains behind the tunnel were known as "The Great Storm Crest". The postcard below shows the west portal of the tunnel with the viaduct. When built, the two lane roadway was 24 feet wide. Broad by the road standards in 1916, ever increasing automobile and truck traffic soon obsoleted the narrow roadway and tunnel. In 1937, the construction and opening of the Tooth Rock Tunnel removed mainstream traffic from the Mitchell Point Tunnel. Below, the picture shows the tunnel under construction in 1915. Notice the ladder that workers would climb to access the tunnel during this phase of construction. The Mitchell Point Tunnel was a part of the original route of the Historic Columbia River Highway from 1916 thru 1932. Built under the supervision of John Elliot, a CRH engineer, the idea was taken from a similar tunnel located in Lucerne, Switzerland. Inspired by a photo that showed four windows and a tunnel overlooking Lake Uri and the Swiss Alps, Elliot fashioned his tunnel with five windows with views of the Columbia River, Mount Ranier and Mount St. Helens. The tunnel took over 8 months of blasting in 1918 and was a huge engineering feat. It solved the problem of traversing the roadway around or thru a prominent rock mountainside the Indians called Storm Crest. The tunnel was carved thru the natural riverbank's basalt cliff and was created with dynamite blasting and hand hewn labor. It was a spectacular accomplishment and a major highlight of the Columbia River Highway. The tunnel served as primary car and truck thoroughfare until 1932, when the Tooth Rock Tunnel was opened offering an alternative route for travelers. Eventually, the tunnel became a one-way passage with the addition of a signal which controlled the traffic flow. In 1953, the tunnel was closed and was sealed with brick and mortar. In 1966, the tunnel was dynamited to clear the way for the new section of I-84. All that remains today is the roadway floor on a shelf 95 feet above the river where the tunnel used to sit. The Mitchell Point Tunnel viewed from the Columbia River bank below.