From the record
“The Morton County WPA Bridge, near Richfield, Kansas, United States, is a stone multi-arch bridge that was built from 1936 to 1939 by the Works Progress Administration (WPA). It was listed on the National Register of Historic Places in 1986.”
Wikipedia article Morton County WPA Bridge, CC BY-SA 4.0.
One of 7 National Register listings published here for Morton County · listed in 1986 · category: Structure · built in 1936.
Sources: the Wikipedia article · the National Register database, National Park Service