From the record
“The Hooker County Courthouse, located on Cleveland Ave. between Railroad and 1st Sts. in Mullen, Nebraska, is a courthouse building of Hooker County, Nebraska. It was a work of Grand Island architect Oscar R.”
Wikipedia article Hooker County Courthouse, CC BY-SA 4.0.
One of 1 National Register listings published here for Hooker County · listed in 1990 · category: District.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service