Originally determined eligible in the Caltrans 1985 Historic Concrete Arch Bridges in California Thematic Resources study. In 2004, it was individually listed on the National Register under the Historic Highway Bridges of California MPS, and it was confirmed eligible again in the 2005 Caltrans Historic Bridge Inventory update: Concrete Arch Bridges.
First Street Bridge is a two-lane, reinforced-concrete haunched T-girder bridge built with the "poured-in-place" method. The bridge features a center arch flanked on each side by a closed, incised spandrel and a slightly raised pilaster. Beneath each pilaster are a stubby buttress and pier with a projecting top band.