I have some information on your aunt/great aunt Elizabeth AHRENS KOESTER as gleaned from her death certificate.Someone in my family also has a lovely photo of her in old age, apparently taken in California.However, I have not been able to find any information on her parents or brothers and sisters until seeing your post.
PARAPHRASED FROM DEATH CERTIFICATE: The widow of William KOESTER, namely Elizabeth KOESTER, was born 27 May 1848, in Mechlinburg (sic--should be Mecklinburg), Germany, and died resident at 2715 Zoe Avenue, Huntington Park, Los Angeles County, California, on 23 Jan 1939.She had lived in Huntington Park for 15 years, California for 33 years and in the United States for 74 years.From that information I conclude that she immigrated to the U. S. when she was about 16 years old.Her father's name is listed on the death certificate as Shoemaker AHRENS (which seems odd to me...are they confusing his name and his occupation perhaps, or could his first name have been SCHUMACHER, the more German spelling of a family name???).Her father is listed as being from Germany but of an unknown town.The mother is listed as being from Germany but with unknown name and unknown town.Elizabeth KOESTER was buried in Inglewood Park Cemetery (with lots of well known celebrities--see findagrave website).
The informant for the death certificate was Carrie M. CHAPLIN of the same address.Carrie was the daughter Elizabeth lived with after she was widowed.I have seen the obituary that appeared in the Terre Haute, Indiana, newspaper (Terre Haute Tribune), and I think it mentioned another surviving daughter was also living in California at the time. My husband's grandfather was Frederick KOESTER, another of Elizabeth AHRENS KOESTER'S children.
Elizabeth's married life and childbearing years were spent in Terre Haute, Vigo County, Indiana. How she came to be there and whether that was her first U. S. destination upon immigration, I do not know.There were and are a few Ahrens in Terre Haute, but I have not been able to discover whether they are related. Her husband William Koester's tombstone appears on findagrave's website for that city.Her name is also engraved on the same tombstone but WITH NO DATES which is what made me realize she probably was buried elsewhere, as I eventually found to be the case.
I would be happy to learn what other information you have about her siblings, her parents and her town of origin in Mecklinburg area of Germany.Regards, Maribeth