Mr Denis Lennon was born on 9 December 1891 in Currycreaghan, Ballymahon, Co Longford, Ireland.
He was the son of William Lennon (b. 1846), a farmer, and Bridget Mullin (b. 1853), Longford natives who had married in the Spring of 1887. One of six surviving children from a total of seven, Denis' surviving siblings were: Eliza (b. 1887), William (b. 1889), John (b. 1893), Anne Maria (b. 1898) and Kate (b. 1899).
On both the 1901 and 1911 census records Denis' family were living in house 12 in Currycreaghan; he would be absent from the 1911 census with his family however and was listed elsewhere as a shop assistant and living with Delia Mullin and her family of house 3, Clarinbridge, Co Galway. Delia's youngest child was an 18-year-old daughter named Mary.
Denis and Mary, the latter not long out of convent school, fell in love and made plans to steal away to America. They boarded the Titanic at Queenstown as third class passengers (ticket number 370371 which cost £15, 10s) and were using the names Denis and Mary Lennon.
Mary's brother Joe (and possibly also her mother) reportedly pursued the couple all the way to Queenstown, Joe carrying a loaded firearm in his fury, but they reached the dock too late.
Denis Lennon, along with Mary Mullin, died in the sinking. Their bodies, if recovered, were never identified.