Michael Grady

 We know from Thomas Grady and Mariah Dempey's marriage certificate from 1876 that her father's name was Bernard, and his father was Michael.

Plus, we know Michael rented land in Derreentiege from the Griffith's Valuation of 1857.

Plus #2, we know civil birth records only started around 1864, on pain of penalty for failing to register a birth.

So, on to church baptism records (and Finola's brave foray to search through them):

https://registers.nli.ie/registers/vtls000632060#page/66/mode/1up

Nov 10, 1848. "Martin of Michael Grady & Ellen Ganley. Sps Wm Fitzmorris. Derentighe"

Is this Thomas's father Michael?

Or is this him?

https://registers.nli.ie/registers/vtls000632060#page/82/mode/1up

June 20, 1852. "John of Michael Grady & Cath Waldron. Sps Maria Waldron. Dereentighe".

We think Thomas had a brother John (see Castlefield blog). How many Michael Gradys could there be in Derreentighe, a townland of 10 homes?

That might not be him, but this is:

https://registers.nli.ie/registers/vtls000632060#page/90/mode/1up

Baptised Oct 25, 1852. "Thomas of Michael & Mary Grady. Sps Martin Commons & Maria ???, C.reliagh".