From the record
“The Elmore County Courthouse is a historic building in Mountain Home, Idaho, and the courthouse of Elmore County, Idaho. Johnson with sandstone from Boise, and it was designed in the Classical Revival style by Wayland & Fennell.”
Wikipedia article Elmore County Courthouse (Idaho), CC BY-SA 4.0.
One of 23 National Register listings published here for Elmore County · listed in 1987 · category: Building · built in 1916, Neoclassical architecture.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service