From the record
“Saltpeter Cave, in Carter Caves State Resort Park near Olive Hill, Kentucky. It was listed on the National Register of Historic Places in 2001.”
Wikipedia article Saltpeter Cave, CC BY-SA 4.0.
One of 3 National Register listings published here for Carter County · listed in 2001 · category: Site.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service
