I met someone today who was researching her Hanlon/O'Hanlon ancestors; they lived in the Parish of Clonduff in the south of Co Down and to the east of Newry.
I've just done a little research on this family. Michael Hanlon married Annie Morgan in 1892. He was baptised in 1857 along with a twin sister Anne. I've found an 1881 wedding between an Anne Hanlon and John Gilmore [son of Peter], both living in the same townland at the time of their marriage. Michael and this Anne have the same father - Michael - and lived in the same townland so could be the twins who were baptised in 1857. Michael snr was married to a Mary Ann Doran.
Michael jnr died in 1938, aged 79, and there's an abstract of his will on the PRONI website.
I've found, in this Rathfriland district, the deaths of a Michael Hanlon [married] in 1876, aged 54 and a Mary O'Hanlon [widowed] in 1894, aged 75. Perhaps these were Michael jnr's parents.