From the record
“DeKalb County Courthouse is a historic courthouse located in Maysville, DeKalb County, Missouri. Eckel of Eckel & Aldrich and built in 1939.”
Wikipedia article DeKalb County Courthouse (Missouri), CC BY-SA 4.0.
One of 3 National Register listings published here for DeKalb County · listed in 1998 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service