From the record
“The Fred Robinson Bridge in Montana is a four-span steel-girder bridge over the Missouri River between Fergus County and Phillips County that was listed on the National Register of Historic Places in 2012. It is the "best documented" bridge in Montana and is "magnificent", according to its NRHP nomination.”
Wikipedia article Fred Robinson Bridge, CC BY-SA 4.0.
One of 48 National Register listings published here for Fergus County · listed in 2012 · category: Structure.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service