While visiting dear daughter over Spring Break, I had a rare day to myself and decided to go find the historic Leonard barn. So I stopped at the WSU visitor center and they told me where it is (they were so nice). I drove a long ways on a kind of paved road and missed it, but ended up in Moscow, ID. While there I asked their visitor center where it was. They were really nice too. After spending some quality time in Moscow, I went back on the long, kind of paved road and this time I actually found the barn! I would have guess that it was in Pullman or unincorporated Whitman County, but documentation shows it in Colfax.
The Leonard Barn, is located on Old Moscow Road. It was built in 1917 and restored in 2001. Originally built to house cows, horses, hay and grain, and the owner was a farmer/educator. The restoration included replacing the cupola that was blown off during a windstorm. The barn isn’t actually round, but instead it is a twelve sided polygon. It was placed on the National Register of Historic Places in 1986 and the nomination form is here.