I was just in Ireland and did not have an opportunity to go to Derrycreigh but I was able to visit Ross Castle. According to some old family letters Julia Donoghue (O'Donoghue) Cadogan, married to Cornelius Cadogan (my great-grandfather) was a direct descendent of the clan chief O'Donoghues Mor (Ross) who built Ross Castle in the late 15th century. I have not been able to find any birth information about Julia, or her husband Cornelius.
Paula Collins and I are also related through the Cadogan brothers and sisters that came to the US.
Would you have any further information on Julia or Cornelius?
Look forward to hearing from you.