Red Rock Bridge, Railway bridge at Topock, Arizona.

The Red Rock Bridge was a single-track steel cantilever through-truss bridge across the Colorado River at Topock, Arizona. Its 990-foot (300 m) span included a 330-foot (100 m) suspended center span, stood 41 feet (12 m) above high water, and used 750 tons of steel. It rested on red sandstone piers, one on each bank 660 feet (200 m) apart and a third in the river 140 feet (43 m) from the west bank.

Construction of this bridge began in 1890 to replace an earlier wooden crossing that suffered repeated flood damage during spring runoff. The crossing initially served rail traffic before being adapted for other purposes in subsequent decades.

The bridge carried U.S. Route 66 traffic from 1947 to 1966, after its railroad ties were replaced with a concrete road deck. It stood within the Havasu National Wildlife Refuge, designated in 1941 for migratory birds along 30 miles of the lower Colorado. Only concrete pilings remain on both banks.

The bridge itself no longer exists: it was dismantled in 1976, leaving only concrete pilings on both banks of the Colorado. Visitors reach the site via Topock, Arizona, and can view the river crossing from the banks; the neighbouring Old Trails Bridge still stands about 240 metres downstream, now carrying a gas pipeline.

The bridge was designed by John Alexander Low Waddell, who supervised its construction, and it was built in eighty days. When completed in 1890 it was the largest cantilever bridge in the United States, carrying 750 tons of steel on piers of red sandstone quarried at Prescott Junction.