I believe it was Slippery Rock. Did you know that Butler County is one of the only places that still had a one room school house in the 1950's and 1960's??? My mom was born in 1933 and didn't go to one room school house. I moved here quite awhile ago and was flabbergasted when I found out. I have a close friend that was born in 1951, and she still went to a one room school house in slippery rock. Could be Harrisville had the same thing and it has been torn down by now. At least lets hope. I was truly shocked at that. WOW. My grandma was born in 1912 & went to a one room school house, but 1951 and beyond. You might want to check the Butler Library, hopefully the info was not destroyed out of shame.