Bestsy Hermundsdatter Trulsen -Lewis A Knudstson 1

I am trying to locate any information in regards to my great, great grand parents Betsy Hermundsdatter Trulsen 1849? Lewis Lars Andreas Bruntviet Knudtson 1848? I had births in Iowa, however I am unable to find any information. I did see a census that a possible birth place is Norway Thank you lori johnson