Van Duzen River Bridge, Spanning Van Duzen River at CA State Highway 101, Alton, Humboldt County, CA

Significance: The Van Duzen River Bridge, also known as the Alton Bridge, was determined eligible for listing in the National Register of Historic Places in 1986. It represents a transitional design in the evolution of concrete arch bridges, and is the earliest surviving bridge designed under the direction of Harlan D. Miller, California's second state bridge engineer and the man most responsible for providing engineering design and aesthetic direction for California bridges between 1924 and 1940.
Survey number: HAER CA-129
Building/structure dates: 1924- 1925 Initial Construction