From the record
“The Pyramid Guard Station, in Rio Blanco County, Colorado near Yampa, Colorado, was built in 1934. It is located off County Route 8 in Routt National Forest, between Dunckley Pass and Ripple Pass.”
Wikipedia article Pyramid Guard Station, CC BY-SA 4.0.
One of 7 National Register listings published here for Rio Blanco County · listed in 2008 · category: District · built in 1934, rustic architecture.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service