My mom and I have been doing research on her paternal grandmother's family, which had settled in Butte, MT, whose ethnic background has always been a huge mystery to us.
Growing up, my mom was frequently mistaken for Italian or Greek because of her dark, Mediterranean appearance. She and her sister remember hearing from their dad that his mother's family was Native American, but he was being facetious. Meanwhile, my mom's aunt told her son they were French Canadian. What's more is that the aunt had all these pictures of the family, but once told her son she was going to throw them away or burn them because "nobody would care about the people in them." On top of that, my mother remembers her maternal grandmother and great-grandmother reacting negatively when they observed that she actually resembled her paternal grandmother. So it's obvious that whatever these people were, there was an effort to hide it, and we've been trying to figure it out ever since.
We recently, for the first time, got to see pictures of what these people looked like, and it honestly has us flummoxed. As you can see from the photos, they all look pretty exotic - too much so to simply be dark-complected people of British descent or Black Irish - and we've looked into numerous possibilities - Jewish, Romani, Melungeon, etc. - but have come up short in every case. Census records going back more than 200 years all say they're WASPs.
There are other things, too. According to Census records, my great-great grandparents were both born in Utah, my great-great grandfather, Marion Collett, to a Mormon family, and my great-great grandmother, Laura Horn, to a family originally from South Carolina. But when my great-grandaunt filled out her dad's death certificate, she said he was born at sea, while my great-great grandmother's obituary says she was born in Canada. Also, they had an older daughter, Waneta, who committed suicide in 1909 on the night before her wedding, which was to take place in Helena. With exception to my great-grandmother, who married an Irish Catholic, the other sisters all married men who had similar appearances; Lucretia married George Robinson, from Milwaukee, and Pearl married Howard Sylvester, from Kansas.