From the record
“District No. 70-Hoff Rural School near Adams, North Dakota was built in 1885. It was listed on the National Register of Historic Places in 2008.”
Wikipedia article District No. 70-Hoff Rural School, CC BY-SA 4.0.
One of 15 National Register listings published here for Walsh County · listed in 2008 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service