The I Street Bridge is a double-deck steel truss bridge with fixed and swing spans. The bridge has thirty-three spans which range in length from seven feet to 390 feet. The overall length of the bridge is 2,194 feet. The lower deck carries the double-track main line of the Southern Pacific Railroad. The upper deck carries State Route 16 with two lanes of traffic and two pedestrian sidewalks.

The I Street Bridge replaced the Southern Pacific's earlier timber Howe truss swing span bridge at the same location. The earlier single-track bridge had been in use since 1867 and had become a severe bottleneck in the Southern Pacific's double-track mainline.

Southern Pacific Railroad and the counties of Sacramento and Yolo began construction in June 1910.

The bridge is also listed on the National Register for Sacramento County.

Adapted from the NRHP nomination.