Marquam Bridge, Spanning Willamette River at Interstate Highway 5, Portland, Multnomah County, OR

Significance: The Marquam Bridge is distinctive as the first Portland span constructed to serve the Interstate freeway system, as well as the first double deck freeway bridge in the state. The structure's functional design reflects the evolution of transportation planning occurring in the development of the Interstate system. A prominent feature in the city scape, the bridge is a primary link in the high speed traffic corridor through Portland. It is unusual as the city's first bridge built exclusively for vehicular use and also as the first of the ten Willamette River bridges in Portland to receive extensive seismic retrofitting.
Survey number: HAER OR-106
Building/structure dates: 1962-1966 Initial Construction