I have no connection to your Horan family but saw your posting.
I checked RootsIreland and found no additional info. There is a tree on Ancestry.com that offers the following. You might already have. The tree suggests Mary might have died in Lancashire. He mother also ended up in England.
Good wishes- Mary
Possibly Mary Horan’s birth record from Ancestry.com
Name
Mary Horan
Baptism Age
0
Event Type
Baptism
Birth Date
1858
Baptism Date
7 Jun 1858
Baptism Place
Tipperary, Tipperary, Ireland
Diocese
Cashel and Emly
Father
Michl Horan
Mother
Ellen Mockler
1891 England Census. I think she was living with her brother Robert.
Name: Robert Horan
Gender: Male
Age: 33
Relationship: Head
Birth Year: 1858
Spouse: Catherine Horan
Child: Robert Horan
Mary E Horan
Catherine Horan
Alice Horan
Margaret Horan
Birth Place: Ireland
Civil Parish: Blackburn
Ecclesiastical parish: St Thomas
Residence Place: Blackburn, Blackburn, Lancashire, England
Registration District: Blackburn
Sub registration district: Blackburn Southern
ED, Institution or Vessel: 25
Neighbors:
Piece: 3406
Folio: 24
Household Members: Name Age
Robert Horan
33
Catherine Horan
32
Robert Horan
9
Mary E Horan
8
Catherine Horan
4
Alice Horan
2
Margaret Horan
10/12
Mary Horan
29
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Name: Robert Horan
Baptism Age: 0
Event Type: Baptism
Birth Date: 1855
Baptism Date: 28 Dec 1855
Baptism Place: Tipperary, Tipperary, Ireland
Diocese: Cashel and Emly
Father: Michl Horan
Mother: Ellen Mockler
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Possible sister
Name: Margaret Horan
Baptism Age: 0
Event Type: Baptism
Birth Date: 1852
Baptism Date: 25 May 1852
Baptism Place: Tipperary, Tipperary, Ireland
Diocese: Cashel and Emly
Father: Michl Horan
Mother: Ellen Mockler
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