I recently traveled to Helena, Montana on a project which involved documenting part of the Missouri River. We set up filming at a location called Mountain Palace on the Missouri River near Cascade, Mt. This location has expansive views of the Big Belt Mountains and is just up the road from Hardy Bridge, which you can see in the panoramics and as well as the embedded video clips.
Hardy Bridge was built in 1931 and is listed in the National Register of Historic Places. The bridge was featured in the 1987 film The Untouchables, starring Kevin Costner and Sean Connery.