From the record
“The Union League of America Hall is a site on the National Register of Historic Places located in White Sulphur Springs, Montana. It was added to the Register on August 20, 1998.”
Wikipedia article Union League of America Hall, CC BY-SA 4.0.
One of 6 National Register listings published here for Meagher County · listed in 1998 · category: Building · built in 1867, Greek Revival architecture.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service


