Family from Aal, Buskerud, Norway

I'm looking for my family who are from the Hallingdal valley in Buskerud Fylke, Norway. My Great Great Grandpa, Knut Paulson, immigrated to America from Hallingdal, Norway in 1858. His parents were Paul & Magnel (Knutsdatter) Peterson. He was born 6 May 1835 and died 17 May 1927. I'm just wondering if my Great Great Grandpa had any brothers/sisters?? So if I could find out some info from Norway...then I could find out the info I'm looking for. That's all the info I know about my Great Great Grandpa when he lived in Norway. Thanks, John