From the record
“The Slayton Mercantile Co. is a site on the National Register of Historic Places located at Main and First Streets in Lavina, Montana. It was added to the Register on December 28, 2000.”
Wikipedia article Slayton Mercantile Co., CC BY-SA 4.0.
One of 7 National Register listings published here for Golden Valley County · listed in 2000 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service

