From the record
“The Toston Bridge is a site on the National Register of Historic Places spanning the Missouri River, on an abandoned segment of old U.S. It was added to the Register on July 20, 2005.”
Wikipedia article Toston Bridge, CC BY-SA 4.0.
One of 11 National Register listings published here for Broadwater County · listed in 2005 · category: Structure · built in 1920.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service