From the record
“The Triangle Lake Round Barn, located west of Eugene, Oregon, was built between 1946 and 1949, and added to the National Register of Historic Places on July 3 2017.”
Wikipedia article Triangle Lake Round Barn, CC BY-SA 4.0.
One of 123 National Register listings published here for Lane County · listed in 2017 · category: Building.
Sources: the Wikipedia article · the National Register database, National Park Service