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See third record on this link. Catherine was born in 1878 and her father was Patrick https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1878/02963/2085604.pdf
The family lived in Ross townland in Killeagh civil parish in Co. Meath Killeagh parish is in the northwest corner of Co. Meath near where Westmeath, Meath, Longford and Cavan meet. The RC parish is Mount Nugent which covers parts of Westmeath, Meath and Cavan.
Catherine had at least six siblings: Patrick 1871 Edward 1872 Maria 1874 Owen 1876 Ellen 1882 Margaret 1884
Catherine's mother Mary Mulligan Geelan died in 1886 (second record) from consumption https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1886/06240/4786352.pdf The father Patrick was a stone cutter
I looked for Geelan families in Ross in the 1901 census http://www.census.nationalarchives.ie/pages/1901/Meath/Killeagh/Ross/1619408/ This is likely Catherine's brother Patrick and his wife and child. Also found her brother Owen who was living with another family http://www.census.nationalarchives.ie/pages/1901/Meath/Killeagh/Ross/1619420/ Owen was a stone cutter.
Patrick and Owen were not in the area around Ross in the 1911 census.
Let me know if you have any questions.