San Joaquin River Viaduct, High-speed railway bridge between Fresno County and Madera County, United States

The San Joaquin River Viaduct is a railway bridge that spans across the valley floor connecting Fresno and Madera County. It features a series of reinforced concrete supports designed to carry trains safely over the river channel below.

In 2012 the City of Fresno recommended a through-arch design with return arches to ease the transition to the flanking box girder segments. The bridge belongs to California High-Speed Rail's Construction Package 1, awarded in August 2013; statnamic load testing on the riverbed followed in February 2015 and construction began in April 2016. Concrete was placed at the east archway by February 2019, and the viaduct was deemed completed in May 2021.

In 2012 the City of Fresno asked for a through-arch design with return arches, so the structure would ease into the adjoining box-girder spans and serve as a landmark on Fresno's northern approach. The 2016 conceptual drawings dropped the return arches, leaving the concrete arch span that was cast in 2019 and finished in May 2021.

The viaduct crosses the San Joaquin River immediately upstream of the Union Pacific and State Route 99 bridges, on Fresno's urban north side. The tracks also pass over Herndon Avenue and Golden State Boulevard, from which the concrete arches and the pergola over the Union Pacific Fresno Subdivision can be seen. The river crossing lies on the Fresno–Madera county line.

The river crossing sits immediately upstream of two other bridges over the San Joaquin: the Union Pacific Railroad bridge and the California State Route 99 bridge. The viaduct's concrete arches were cast in place in 2019, with crews forming the west archway while concrete was placed at the east archway.