G1: Thomas Dempsy (Bernard's brother; Mariah's uncle)

See Bernard Dempsy blog entry for 1857 Griffith's Valuation entry for brother Thomas and Bernard Dempsy. 

Census, 1901:

http://www.census.nationalarchives.ie/pages/1901/Roscommon/Ballinlough/Cloonreliagh/1663670/

Thomas has died by 1911 census. His son Thomas is now head of family:

http://www.census.nationalarchives.ie/pages/1911/Roscommon/Ballinlough/Cloonreliagh/760345/

Daughter Margaret, born 1865:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1865/03559/2310491.pdf

Margaret eventually moves to the US, and takes in her sister Sarah's orphaned children, Thomas and Sarah.

Thomas's daughter Maria's marriage, Jan 28th, 1875: (this is NOT the Mariah Dempsy that marries Thomas Grady!)

https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1875/11197/8103309.pdf

Thomas dies, Dec 10th, 1902, age 80:

https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1902/05676/4599118.pdf

Thomas's son Patrick's marriage to Celia Kilcourse January 3rd, 1877 (this is his son, not his grandson in the 1911 census above). Celia signed as Mary? Correction shows that too?

Patrick Dempsey and Sarah Kilcourse of Keyfield (her hometown) have a son Thomas Nov 4, 1884. We see Celia & Sarah names used interchangeably.

Their first son, Michael, born 1877:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1877/02994/2097196.pdf

Son Patrick 1881:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1881/02812/2031645.pdf

Their son Thomas born Nov 4, 1884:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1884/02665/1982184.pdf

However, he does not survive, dying Dec 13, 1885:

https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1885/06266/4794901.pdf

Daughter Mary, 1886:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1886/02578/1952800.pdf

Thomas's son Thomas marries Bridget Quinn March 9, 1881:

https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1881/10994/8019796.pdf

They have a son Thomas, May 8, 1886:

And a son Patrick born Dec 6th,1890:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1891/02396/1893404.pdf

Margaret, born May 26, 1894:

https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1894/02246/1845438.pdf

She dies December 26, 1911, age 17:

https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1912/05370/4497694.pdf