Norway to America - 1861

My great grandparents and grandfather emigrated from Gransherad to America (or Canada?) in 1861, and settled in Wisconsin. I was told previously they most likely would have departed from Porsgrunn or Skien. Is there any possibility of locating any information, e.g. name of ship, route, and/or passenger list? I suspect I know the answer already, but just want to confirm so I don't waste more time looking. I've been told there are no records anywhere of ships and/or passengers from Norway to America or Canada in 1861, yet I have -- in the past -- come across one or two records; however, I can't recall which website I saw them on.