From the record
“The Little Missouri Bank Building, located on the northwest corner of Main Street and First Street in Camp Crook, South Dakota, was built in 1918. It was listed on the National Register of Historic Places in 1987.”
Wikipedia article Little Missouri Bank Building, CC BY-SA 4.0.
One of 13 National Register listings published here for Harding County · listed in 1987 · category: Building · built in 1918.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service