From the record
“The Birch Lodge, also known as the Birch Lodge Hospital and Summer Resort Sanitarium or the Trout Lake Sanitarium, is a resort facility located on the northern shore of Trout Lake, off County Route H-40, .6 miles (0.97 km) west of MI-123, in Trout Lake Township, Michigan. It was listed on the National Register of Historic Places in 1996 and designated a Michigan State Historic Site in 1987.”
Wikipedia article Birch Lodge, CC BY-SA 4.0.
One of 26 National Register listings published here for Chippewa County · listed in 1996 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service