From the record
“The Spokane River Bridge at Long Lake Dam, at Long Lake Dam near Reardan, Washington, is a historic 486-foot (148 m) concrete bridge that was built in 1949. It was a work of the State Department of Highways and of Henry Hagman.”
Wikipedia article Spokane River Bridge at Long Lake Dam, CC BY-SA 4.0.
One of 8 National Register listings published here for Lincoln County · listed in 1995 · category: Structure · built in 1949.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service