Rahan Lodge was built by Henry Petty, Earl of Shelbourne as a hunting lodge abour 1740. It was built on the site of an old castle. He died without issue and left all of his estates to his nephew John Fitz-Maurice, son of the Earl of Kerry.
Fitz-maurice was created Earl of Shelbourne. He died in 1760 and was succeeded by his son William, first Marquis of Lansdowne who was Prime Minister of the United Kingdom 1782-1783. He married the Lady Lousia Fitz-Patrick daughter of the first Earl of Upper Ossory and sister of Richard Fitz-Patrick M.P. of Maryborough 1792-1793.
The Marquis of Landsdowne sold the Rahan Estate in 1803 to Denis O'Brien, a Dublin Merchant. O'Brien left it to his daughter Sister Mary Clare. She gave it to her brother John O'Brien who left it to his wfe Elizabeth Ball. She was called Lady O'Brien by the people of Rahan.
Lady O'Brien entertained at the Lodge such personalities as Daniel O'Connell, Dr Murray, Archbiship of Dublin and Mother Mary Aidenhead, the foundress of the Irish Sisters of Charity. She left no issue and her will gave the Lodge to her nephew County John Sherlock who in turn gave it to his brother David M.P.
David Sherlock was born in Dublin in 1814, educated at Trinity College and called to the bar. He died in 1884. He left Rahan Lodge to his son (David 11). David Sherlock 11 was born at Rahan Lodge in 1850. He had three sons, one was Major Edward Sherlock who married Lu Kelly in 1940. They had two daughters Zeena and Hazel. Major Sherlock died in 1953 and Mrs Sherlock remained in the Lodge until 1967 when it was sold to the Land Commission.