There seem to be a lot of Mary Campbells born circa 1869, but in light of the possible death of the mother, I thought this one in the 1880 census in Westchester County was interesting. There is a Mary of the right age listed as in school, and all the people on the pages around her seem to be either kids in school or people who might work at a school, like a cook or laundress. I'm not sure what school it is, but maybe it's a place where kids got shipped off to when parents couldn't care for them. https://www.familysearch.org/search/ark:/61903/1:1:MZNJ-6D5
That might not be her.
image 59 of this set has a note that says "this ends the inmates of the male department of the protectory"
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it is probably "the New York Catholic Protectory, ... village of West Chester (now the Bronx)"
https://academicworks.cuny.edu/cgi/viewcontent.cgi?article=1229&context=le_pubs-----------
Report of the NY Catholic Protectory
List of Girls in the institution, October 1, 1879
Mary Campbell, received June 14, 1878, age 9, both parents living, religion of parents: Catholic
https://babel.hathitrust.org/cgi/pt?id=uiug.30112050274296&view=1up&seq=466&skin=2021&q1=campbell-------------
I think they stopped including a list of all the residents with the annual report in 1879. I didn't see a list of children in the institution in October 1880.
They had a list of children admitted from October 1879 to Oct 1880, and I didn't see a Mary Campbell on the list.
