Andrea Mathilda Ludvigsdatter Andersen to America

Hi everyone. I'm looking for my great grandmothers family, Andrea Mathilda was born in Bergen Dec.4,1847 Her father Ludvig Cornelius Andersen b.1816 Førde, Sogn og Fjordane, Norway Her mother Anne Oline Arnesdatter b. 1829 Bergen I have found 3 sisters born in Bergen Olina Sophie b. 1850 Oliva Sophie b. 1851 Marie Karoline b. 1853 I have found their families going back in Norway. Census records show her Immigrating abt.1855 I find nothing of Ludwig or Anne in America. I did find Oliva S. marriage 1874 in Cook County To Ole Dahl and upon being widowed moving to Lodi Wisconsin by 1900 She was married in Cook county Illinois in 1872. the first i records i find her in are the 1880 U.S. census As Matilda Dale in Dane county Wisconsin 1900 U.S. census as Mathilda Dahl in Lodi Wisconsin any help will be greatly appreciated Jim