Karen Johannesdatter Monshaugen

Seeking information about my female ancestor, supposedly named Karen Johannesdatter Monshaugen. She is said to have been born in Norway in 1838, but I have no idea where it might be. Her parents are said to be Johans Rasmussen and Ane, and later in life she had a stepmother. Any information would be very much appreciated. With so little information I don't know where to turn. Karen later emigrated to the United States and settled in Wisconsin. She married Gullik Olson and died in 1866.