Snowden Bridge is a high-clearance, vertical-lift railroad bridge, built in 1913, that spans the Missouri River between Roosevelt and Richland Counties in Montana, USA, between Bainville and Fairview, Montana, and near Fort Union Trading Post National Historic Site and the ghost town of Mondak near Montana's eastern border with North Dakota.

The War Department required a movable span on the grounds that large steamboats might venture up the Missouri during the month or so that the river was navigable that far north.

A kerosene engine in the lift house could raise it 43 feet (13 m) in about thirty minutes.

[3] In 1925, a plank roadbed was built for one-way vehicular and foot traffic, while the bridge continued to be used by the Great Northern Railroad.

Although a long bridge with one-way traffic and shared with railroad trains should have been spectacularly hazardous, a 1981 study found that it was "so dangerous that it [was] safe" because drivers were extraordinarily cautious when crossing it.