Seeking Mathilda Olsen born in 1870

I'm seeking information on Mathilda Olsen who was born in 1870 in Norway and immigrated to the US in 1872. She married Hiram Grindall and lived in Cosmos, Minnesota. She had four children with Hiram: Edna, Alice, Ethel and Clifford. On census records she's been listed as Mathilda, Mary, and Marg. She died in Minnesota in 1959. Her death certificate lists her as Mathilda Olson Grindall, and says her mother's maiden name was Swanson. I'm trying to find out any information on her parents and family from Norway. Any help would be greatly appreciated! Thanks, Jenny