From the record
“The Garden City Opera House, at 1st and Railroad Streets in Garden City, South Dakota, was built in 1908. It was listed on the National Register of Historic Places in 1988.”
Wikipedia article Garden City Opera House, CC BY-SA 4.0.
One of 10 National Register listings published here for Clark County · listed in 1988 · category: Building · built in 1908.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service