From the record
“The Big Horn Hotel, on Main St. in Arminto, Wyoming, was built in 1906. It was listed on the National Register of Historic Places in 1978.”
Wikipedia article Big Horn Hotel, CC BY-SA 4.0.
One of 36 National Register listings published here for Natrona County · listed in 1978 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service